List of vacuum tubes

This is a list of vacuum tubes or thermionic valves, and low-pressure gas-filled tubes, or discharge tubes. Before the advent of semiconductor devices, thousands of tube types were used in consumer and industrial electronics; today only a few types are still used in specialized applications.

Heater or filament ratings

Main article: Hot cathode

Vacuum tubes fall into three mainly non-interchangeable categories regarding their heater or filament voltage (some tubes' heaters run at a voltage and current suitable for either series or parallel operation, e.g., 6.3 V at 300 mA).

1. Battery types, with a low-power filament operated usually from 1 to 2 V; all filaments in a design are rated at the same voltage and are connected in parallel. They are usually directly heated to save heating power (therefore requiring a DC current), except if the (due to the voltage gradient along the filament) poorly defined cathode potential impedes the function of the device, as is the case e.g. with AM detector diodes with filament voltages of 1.9 V or more; in such cases, indirect heaters were employed and marketed as unipotential cathode at the time.
   • 1.25 V for one NiCd cell
   • 1.4 V for one Leclanché cell, later for one dry cell
   • 1.7 to 1.9 V for one lead-acid cell with a variable filament resistor (German: Heizregler)
   • 2 V for one lead-acid cell
   • 2.5 V for two NiCd cells
   • 4 V for two lead-acid cells
2. Types for AC-only equipment with a mains transformer, or for car radios; all tube heaters are rated at the same voltage and fed in parallel from a transformer winding or from the car battery, usually 6.3V (domestic AC-only, and 6V car radios) or 12.6V (mainly 12V car radios). Most are indirectly heated.
3. Types for equipment designed to run on either AC or DC mains power (ac/dc) with no mains transformer; all heaters are connected in series, possibly with an additional ballast tube (barretter) or power resistor chosen so that the sum of the heater and ballast voltages equals the mains voltage. All tubes must be rated at the same heater current, typically 100, 150, 300 or 450 mA. They are always indirectly heated.

The currents drawn by parallel-connected types, and the voltages across series-connected types, vary widely according to the tube's heating power requirements. Otherwise identical tubes were manufactured in several variants with different heater characteristics (but usually the same power, e.g. 6.3 V/300 mA and 12.6 V/150 mA). See, for example, the RCA Receiving Tube Manuals.

In half-indirectly heated tubes the cathode and one side of the filament share the same pin.

Tube bases

Main article: Tube socket

Numbering systems

North American systems

RMA system (1942)

Main article: RMA tube designation

The system assigned numbers with the base form "1A21", and is therefore also referred to as the "1A21 system".

First digit Filament/heater power rating:

• 1 No filament/heater; cold cathode or solid state device
• 2 Up to 10 W
• 3 10-20 W
• 4 20-50 W
• 5 50-100 W
• 6 100-200 W
• 7 200-500 W
• 8 500W-1 kW
• 9 More than 1 kW

Next character: Function:

• A Single element (ballast, barretter)
• B Two-element device such as:
  • Diode

• TR (Transmit/receive) cell, cold-cathode water vapor discharge tube for use in radar systems, short-circuits the receiver input to protect it while the transmitter operates
• ATR (Anti-transmit/receive) cell, cold-cathode water vapor discharge tube for use in radar systems, decouples the transmitter from the antenna while not operating, to prevent it from wasting received energy
• Spark gap

• C Triode
• D Tetrode
• E Pentode or beam power tetrode
• F Hexode
• G Heptode
• H Octode
• J Magnetically controlled types, usually incorporating a resonator (essentially, magnetrons)
• K Electrostatically controlled types, including a resonator (klystrons and inductive output tubes)
• L Vacuum capacitors
• N Crystal rectifiers (This designation lived on as the "N" in the EIA/JEDEC EIA-370 solid state device numbers standard, like 2N2222)
• P Photosensitive types (phototubes, photomultipliers, camera tubes, image converters)
• Q Resonant vacuum cavities
• R Ignitrons and mercury arc rectifiers
• S Vacuum switches
• T Storage, radial beam, and deflection control tubes (no known examples assigned)
• V Flash tubes
• W Traveling-wave tube
• X X-ray tube
• Y Thermionic converter

The last 2 digits were sequentially assigned, beginning with 21 to avoid possible confusion with receiving tubes or CRT phosphor designations. Multiple section tubes (like the 3E29 or 8D21) are assigned a letter corresponding to ONE set of electrodes.

Examples

• 1B23 20 kW, 400 to 1500 MHz Gas-filled, cold-cathode Transmit/Receive Tube (TR cell)
• 1B41 Gas-filled, cold-cathode 9.5 kV, 450 A spark gap
• 1B45 Gas-filled, cold-cathode 14 kV, 450 A spark gap
• 1B49 Gas-filled, cold-cathode 12 kV, 450 A spark gap
• 1C21 Gas-filled, 25 mA_avg, 100 mA_peak, triode thyratron
• 1D21 Strobotron, gas-filled, 50 mA_avg, 5 A_peak, luminiscent tetrode thyratron for use as a stroboscope lamp
• 1P21 9-stage Photomultiplier, spectral S4 response, 11-pin base
• 1P25 Infrared image converter used in WW2 night vision "sniperscopes".
• 1P29 Gas-filled phototube, spectral S3 response, 4-pin base
• 1P39 Vacuum Phototube, spectral S4 response, 4-pin base
• 1S22 10 kV, 20 A Vacuum SPDT switch
• 2C21 Dual transmitting triode, indirectly heated, 7-pin base plus a single top cap for one of the grids
• 2C22 Transmitting triode, indirectly heated, 8-pin base plus dual top cap for grid and anode
• 2C39 Disk-seal-type planar UHF power triode.
• 2C43 Lighthouse-type disk-seal UHF planar transmitting triode, indirectly heated, up to 3.37 GHz, 6-pin base
• 2C51 Dual shielded triode, indirectly heated, 9-pin base
• 2D21/EN91 (PL21, PL2D21, CV797) 100 mA_avg, 500 mA_peak, 10 A_surge, Gas-filled, indirectly heated tetrode thyratron, negative starter voltage, miniature 7-pin base, for relay and grid-controlled rectifier service, used in jukeboxes and computer equipment.
• 2E22 53 W Power pentode, 5-pin base with anode on top cap
• 2E26 Popular amateur 5.3 W VHF beam power tetrode up to 175 MHz, octal base
• 2E30 10 W Directly heated beam power tetrode with deflection screens available on separate pin, miniature 7-pin base
• 2E31 Subminiature, directly heated, fully shielded sharp-cutoff RF/IF pentode, 5-pin all-glass pigtailed, FL
• 2E32 Similar to 2E31, SL
• 2E35 6 mW Subminiature directly heated power pentode, 5-pin all-glass pigtailed, FL
• 2E36 Similar to 2E35, SL
• 2E41 Diode, pentode, FL
• 2E42 Similar to 2E42, SL
• 2F21 Indirectly heated hexode monoscope, Indian Head test pattern, 6-pin base with dual top caps for grid4 and anode
• 2G21 Directly heated triode-heptode mixer, 7-pin all-glass pigtailed
• 2G41 Triode-heptode converter, FL
• 2G42 Similar to type 2G42, SL
• 2J30 to 2J34 300 kW S-band Magnetrons
• 2J55 and 2J56 40 kW X-band Magnetrons for use as pulsed oscillator
• 2K25 25 mW 8.5 to 9.66 GHz reflex Klystron
• 2K50 15 mW 23.5 to 24.5 GHz reflex Klystron
• 2P23 Early image orthicon TV camera tube.
• 3B28 Xenon half wave rectifier; ruggedized replacement for mercury vapor type 866.
• 3C23 1.5 A_avg, 6 A_peak, Mercury-vapor triode thyratron, 4-pin base with anode top cap
• 3C45 45 mA_avg, 1.5 A_RMS, 35 A_peak, Half-indirectly heated hydrogen triode thyratron, 4-pin base with anode top cap
• 3D21 Indirectly heated beam power tetrode, 8-pin base with anode top cap
• 3D22 Gas-filled, 800 mA_avg, 8 A_peak, tetrode thyratron, 7-pin base
• 3E29 Dual beam power tube used in radar equipment; a pulse rated variant of the earlier 829B, 7-pin base with dual anode top cap.
• 4B32 10 kV, 1.25 A_avg, 5 A_peak Xenon half wave rectifier
• 4D21 (6155, Eimac 4-125A) 125 W Glass VHF beam power tetrode
• 4E27 125 W Glass radial-beam power pentode
• 4J31 to 4J35 1 MW S-band Magnetrons
• 5C22 Half-indirectly heated, hydrogen triode thyratron for radar modulators.
• 5D22 (6156, Eimac 4-250A) 250 W, 110 MHz Glass beam power tetrode
• 5J26 500 kW, 1.22 to 1.35 GHz S-band Magnetrons
• 5K70 30 kW S-band reflex Klystron
• 6C21 Triode radar modulator for "hard tube" pulsers.
• 7C23 120 kW Power triode for high voltage pulse operation.
• 8D21 Internally water cooled dual tetrode used in early VHF TV transmitters.
• 9C21 100 kW Water-cooled power triode, directly heated, 4-pin base with dual top caps for grid and anode

RETMA receiving tubes system (1953)

Main article: RETMA tube designation

RETMA is the acronym for the Radio Electronic Television Manufacturers Association, originally the RMA, later RTMA, then EIA (Electronic Industries Association, since 1997 Electronic Industries Alliance).

• The first character group is always a number, consisting of one to three numerals, and very often represents the heater voltage to the nearest whole number - exceptions including 2.0 Volt filament tubes (such as 1C7-G and 1F4) and series heater tubes where the rounding was less exact (such as the 5.9-Volt 5X9 and the 46-Volt 50Y7GT).
• These numerals are followed by one or two letters assigned to the devices in some sort of semi-chronological order of development and introduction to the marketplace,
• and then another single numeral that represents the number of active elements in the tube (including any internal shield plus the heater in indirectly heated tubes - electrodes connected together internally count as one). For example, a 7 could mean a heptode (pentagrid converter) such as the 12SA7-GT, or a pentode with two diodes such as the 7E7, or with one diode and a shield pin such as the 12SF7, or triode with two diodes and a shield pin such as the 6SR7, or a twin-input triode such as the 6AE7-GT, or a double triode such as the 6SN7-GT. Exceptions include the 35L6-GT (with 5 elements, but named for consistency with the 6L6/6L6-G where pin 1 may or may not be connected to a shield, making the sixth element).
• Sometimes a string of up to three Roman letters can be suffixed to the overall number; these generally distinguish various revisions and improvements to the original model or different bulb shapes; use is unsystematic, except that for octal tubes G often indicated a shouldered glass envelope, GT a tubular glass envelope, and neither of these often a metal envelope. When discussing a type in general the letters are often omitted; discussion of the properties of the 6SN7 would tacitly include the 6SN7GT, 6SN7GTB, etc., but not the comparable 6SL7 family. By and large tubes with the same basic designation are interchangeable unless the qualities of an enhanced version are required.
• Lastly, manufacturers may decide to combine two type numbers into a single name, which their one device can replace, such as: 6DX8/ECL84 (6DX8 and ECL84 being identical devices under different naming schemes) or 6BC5/6CE5 (sufficiently identical devices within the RETMA naming system) and even 3A3/3B2, or 6AC5-GT/6AC5-G (where the single type number, 6AC5-GT/6AC5-G, supersedes both the 6AC5-G and the 6AC5-GT).

Often, but not always, vacuum tube designations that differed only in their initial numerals would be identical except for heater characteristics. Exceptions include: the 12BR7 and 9BR7 are unrelated to the 6BR7; the 4BL8/XCF80 is the 4.6 Volt (600mA series heater) version of the 6BL8/ECF80, but the 450mA series heater version is the 6LN8/LCF80 rather than 6BL8.

For examples see below

EIA professional tubes system

A four-digit system was maintained by the EIA for special industrial, military and professional vacuum and gas-filled tubes, and all sorts of other devices requiring to be sealed off against the external atmosphere.

Some manufacterers preceded the EIA number with a manufacterer's code:

• CK Raytheon Company
• GL General Electric Corp.
• F Federal Telephone and Radio (ITT division)
• ML Machlett Laboratories, Inc.
• NL National Electronics, Inc. (Geneva, Illinois, USA)
• NU National Union Electric Corp. (Orange, New Jersey, USA)
• PL Philips N.V.
• SV Svetlana:
  • formerly only JSC "Svetlana" (Russian: ОАО "Светлана"), St. Petersburg, Russia
  • now also a brand of New Sensor Corp., Long Island City, New York, USA, manufacturing in Saratov, Russia
• SY Standard Telephones and Cables Ltd./Brimar (not Sylvania Inc.)
• WL Westinghouse Electric Corp.

For examples see below

West European systems

Mullard-Philips system

Main article: Mullard-Philips tube designation

This system is very descriptive of what type of device (triode, diode, pentode etc.) it is applied to, as well as the heater/filament type and the base type (octal, noval, etc.). Adhering manufacturers include AEG (de), Amperex (us), Dario (fr), La Radiotechnique (fr), Lorenz (de), Mullard (uk), Philips (nl), RCA (us), RFT (de), Siemens (de), Telefunken (de), Toshiba (ja), Tungsram (hu) and Valvo (de).

Standard tubes

This part dates back to the joint valve code key (German: Röhren-Gemeinschaftsschlüssel) negotiated between Philips and Telefunken in 1933-34. Like the North American system the first symbol describes the heater voltage, in this case a Roman letter rather than a number. Further Roman letters, up to three, describe the device followed by one to four numerals assigned in a semi-chronological order of type development within number ranges assigned to different base types.

If two devices share the same type designation other than the first letter (e.g. ECL82, PCL82, UCL82) they will usually be identical except for heater specifications; however there are exceptions, particularly with output types (for example, both the PL84 and UL84 differ significantly from the EL84 in certain major characteristics, although they have the same pinout and similar power rating). However, device numbers do not reveal any similarity between different type families; e.g. the triode section of an ECL82 is not related to either triode of an ECC82, whereas the triode section of an ECL86 does happen to be similar to those of an ECC83.

Pro Electron maintained a subset of the M-P system after their establishment in 1966, with only the first letters E, P for the heater, only the second letters A, B, C, D, E, F, H, K, L, M, Y, Z for the type, and issuing only three-digit numbers starting with 1, 2, 3, 5, 8, 9 for the base.

Notes: Tungsram preceded the M-P designation with the letter T, as in TAD1 for AD1; Vatea (United Incandescent Lamp and Electric Company, Budapest, Hungary) preceded the M-P designation with the letter V, as in VEL5 for EL5.

• First letter: heater/filament type

Heater ratings for series-string, AC/DC tubes are given in milliamperes; heater ratings for parallel-string tubes are given in volts

• A 4 V heater for 2-cell lead-acid batteries and for AC mains transformers
• B 180 mA DC series heater
• C 200 mA AC/DC series heater
• D 1.4 V DC filament for Leclanché cells, later low-voltage/low power filament/heater:

• 0.625 V DC directly heated for NiCd battery, series-heated two-tube designs such as hearing aids. If either filament breaks, further draining of all batteries stops
• Wide range 0.9 V to 1.55 V DC directly heated for dry cells
• 1.25 V DC directly heated for NiCd batteries
• 1.25 V or 1.4 V AC from a separate heater winding on CRT horizontal-output transformers, in half-indirectly heated EHT rectifiers

• E 6.3 V parallel heater; for 3-cell lead-acid vehicle crank batteries (mobile equipment) and for AC mains or horizontal-output transformers
• F 12.6 V DC parallel heater for 6-cell lead-acid vehicle crank batteries
• G 5.0 V AC from a separate heater winding on a mains or horizontal-output transformer for the anode voltage rectifier; later misc.
• H 150 mA AC/DC series heater
• I 20 V heater
• K 2.0 V filament for 1-cell lead-acid batteries, later for AC transformers
• L 450 mA AC/DC series heater; was shifted here from Y
• M 1.9 V, directly heated
• N 12.6 V, indirectly heated
• O Cold cathode (by 1955 this also included semiconductors as these had no heater)
• P 300 mA AC/DC series heater
• Q 2.4 V, indirectly heated
• R Not assigned to avoid any confusion with the older Telefunken "R" system
• S 1.9 V, indirectly heated
• T Customized heater
• U 100 mA AC/DC series heater
• V 50 mA AC/DC series heater
• X 600 mA AC/DC series heater
• Y 450 mA AC/DC series heater, shifted to L to avoid conflicts with the professional tubes system
• Z Cold cathode tube; was shifted here from O after the advent of semiconductors

• Second and subsequent letters: system type

• A Small signal diode
• B Dual small signal diode
• C Small signal triode
• D Power output triode
• E Small signal tetrode
• F Small signal pentode
• H Mixer hexode, special purpose heptode
• K Mixer heptode or octode
• L Power output, beam tetrode or pentode
• M Optical tuning/level indicator
• N Gas-filled thyratron
• P Secondary emission tube - mostly used as third letter
• Q Nonode
• R Resistive element (ballast tube, barretter, photoresistor)
• S Special tube (German: Sonderröhre)
• T Beam deflection tube, or misc.
• W Gas-filled half-wave rectifier
• X Gas-filled full-wave rectifier
• Y Vacuum half-wave rectifier (power diode)
• Z Vacuum full-wave rectifier (dual power diode with common cathode)

E.g. ECCnn is a 6.3 V dual triode; EABCnn has a single detector diode, a common-cathode pair of diodes, and a triode.

• Following digits: model number and base type

For signal pentodes, an odd model number most often identified a variable transconductance (remote-cutoff) valve, whereas an even number identified a 'high slope' (sharp-cutoff) valve

For power pentodes and triode-pentode combinations, even numbers usually indicate linear (audio power amplifier) devices while odd numbers were more suited to video signals or situations where more distortion could be tolerated.

• 1–9 Pinch-type construction valves, mostly P8 bases (P base, 8-pin side-contact) or European 5-pin (B base) and various other European pre-octal designs
• 10–19 8-pin German metal octal, G8A
• 20–29 Loctal B8G; some octal; some 8-way side contact (exceptions are DAC21, DBC21, DCH21, DF21, DF22, DL21, DLL21, DM21 which have octal bases)
• 30–39 International Octal (IEC 67-I-5a), also known as IO or K8A
• 40–49 Rimlok (Rimlock) B8A All-glass miniature valves

• 41w Battery-heated bowl tube (German: Pressnapfröhre)

• 50–59 "Special construction types fitted with bases applicable to design features used"; mostly locking bases: "9-pin Loctal" (B9G) or 8-pin Loctal (B8G); but also used for Octal and others (3-pin glass; Disk-seal incl. "Lighthouse" tubes; German 10-pin with spigot; min. 4-pin; B26A; Magnoval B9D)
• 60–69 Pencil tubes - sub-miniature all-glass tubes, pigtailed (inline fly-leads in place of pins)

—Before 1950s:

• 60–64 All-glass tubes fitted with 9-pin (B9G) bases

• 70–79 Pencil tubes with circular pins or fly-leads

—Before 1950s:

• 70–79 Loctal Lorenz

• 80–89 Noval B9A (9-pin; IEC 67-I-12a)
• 90–99 "Button" B7G (miniature 7-pin; IEC 67-I-10a)
• 100–109 B7G; Wehrmacht base; German PTT base
• 110–119 8-pin German octal; Rimlok B8A
• 130–139 Octal
• 150–159 German 10-pin with spigot; 10-pin glass with one big pin; Octal
• 160–169 Inline wire-ended Pencil tubes; 8-pin German octal
• 170–179 RFT 8-pin; RFT 11-pin all-glass gnome tube with one offset pin
• 180–189 Noval B9A
• 190–199 Miniature 7-pin B7G
• 200–209 Decal B10B; Pro Electron-issued
• 230–239 Octal
• 270–279 RFT 11-pin all glass with one offset pin
• 280–289 Noval B9A
• 300–399 Octal; Pro Electron-issued
• 400–499 Rimlok B8A
• 500–529 Magnoval B9D, Novar; Pro Electron-issued
• 600–699 Inline wire-ended Pencil tubes
• 700–799 Circular wire-ended Pencil tubes
• 800–899 Noval B9A; Pro Electron-issued
• 900–999 Miniature 7-pin B7G; Pro Electron-issued
• 1000- Round wire-ended; special Nuvistor base
• 2000- Decal B10B
• 3000- Octal
• 5000- Magnoval B9D
• 8000- Noval B9A

For examples see below

Special quality tubes

Vacuum tubes which had special qualities (French: Securité - Qualité) of some sort, very often long-life designs, particularly for computer and telecommunications use, had the numeric part of the designation placed immediately after the first letter. They were usually special-quality versions of standard types. Thus the E82CC was a long-life version of the ECC82 intended for computer and general signal use, and the E88CC a high quality version of the ECC88/6DJ8. While the E80F pentode was a high quality development of the EF80, they were not pin-compatible and could not be interchanged without rewiring the socket (the E80F is commonly sought after as a high quality replacement for the similar EF86 type in guitar amplifiers). The letters "CC" indicated the two triodes and the "F", the single pentode inside these types.

A few special-quality tubes did not have a standard equivalent, e.g. the E55L, a broadband power pentode used as the output stage of oscilloscope amplifiers and the E90CC, a double triode with a common cathode connection and seven pin base for use in cathode-coupled Flip-flops in early computers. The E91H is a special heptode with a passivated third grid designed to reduce secondary emission; this device was used as a "gate", allowing or blocking pulses applied to the first, (control) grid by changing the voltage on the third grid, in early computer circuits (similar in function to the U.S. 6AS6).

Many of these types had gold-plated base pins and special heater configurations inside the nickel cathode tube designed to reduce hum pickup from the A.C. heater supply, and also had improved oxide insulation between the heater and cathode so the cathode could be elevated to a greater voltage above the heater supply. (Note that elevating the cathode voltage above the average heater voltage, which in well-designed equipment was supplied from a transformer with an earthed center-tapped secondary, was less detrimental to the oxide insulation between heater and cathode than lowering the cathode voltage below the heater voltage, helping to prevent pyrometallurgical electrolytic chemical reactions where the oxide touched the nickel cathode that could form conductive aluminium tungstate and which could ultimately develop into a heater-cathode short-circuit.)

Better, often dual, getters were implemented to maintain a better vacuum, and more-rigid electrode supports introduced to reduce microphonics and improve vibration and shock resistance. The mica spacers used in "SQ" and "PQ" types did not possess sharp protrusions which could flake off and become loose inside the bulb, possibly lodging between the grids and thus changing the characteristics of the device. Some types, particularly the E80F, E88CC and E90CC, had a constricted section of bulb to firmly hold specially shaped flakeless mica spacers.

For examples see below, starting at DC

Later special-quality tubes had not base and function swapped but were assigned a 4-digit number, such as ECC2000 or ED8000, the first digit of which again denoting the base:

• 1 Miscellaneous
• 2 Miniature 10-pin base (JEDEC F10-61)
• 3 Octal base (IEC 67-1-5a)
• 5 Novar/magnoval base (JEDEC E9-75 and E9-23)
• 8 Noval base (IEC 67-1-12a)
• 9 Miniature 7-pin base (IEC 67-1-10a)

For examples see below, starting at EC

"Z" Cold-cathode SQ tubes had a different function letter scheme:

• A Long-life amplifier tube
• B Binary counter or switching tube
• C Common-cathode Counter Dekatron that makes only carry/borrow cathodes separately available for cascading
• E Electrometer tube
• G Amplifier tube
• M Optical indicator
• S Separate-cathode Counter/Selector Dekatron that makes all cathodes available on individual pins for displaying, divide-by-n counter/timer/prescalers, etc.
• T Relay triode, a low-power triode thyratron, one starter electrode, may need illumination for proper operation if not radioactively primed
• U Low-power tetrode thyratron, may mean:
  • Trigger tetrode, one starter electrode and a primer (keep-alive) electrode for ion availability to keep the ignition voltage constant, for analog RC timers, voltage triggers, etc.
  • Relay tetrode, two starter electrodes to make counters bidirectional or resettable
• W Trigger pentode, two starter electrodes and a primer electrode
• X Shielded Trigger pentode, two starter electrodes, a primer electrode and a conductive coating of the glass envelope inside connected to a separate pin

For examples, see below under Z

Professional tubes

In use since at least 1961, this system was maintained by Pro Electron after their establishment in 1966.

Both letters together indicate the type:

• X High vacuum electro-optical devices
  • XA Phototube
  • XG Miscellaneous
  • XM Character generating cathode ray tube
  • XP Photomultiplier
  • XQ Camera tube
  • XR Monoscope
  • XS Cathode ray charge storage tube
  • XT Memory display tube
  • XV Infrared detector
  • XW Infrared imaging device
  • XX Image intensifier or image converter

• Y Vacuum tubes
  • YA Diode
  • YD Transmitting or industrial, single or dual triode
  • YG Electrometer tube, vacuum gauge
  • YH Traveling-wave tube
  • YJ Magnetron
  • YK Klystron
  • YL Transmitting or industrial, single or dual tetrode or pentode
  • YN Backward wave oscillator
  • YP Electron multiplier
  • YR Crossed-field amplifier
  • YT Pulse modulator tube
  • YY High vacuum rectifier

• Z Gas-filled tubes not employing photosensitive materials
  • ZA Cold cathode indicator tube
  • ZB Microwave switching tube (TR/ATR cells, etc.)
  • ZC Trigger tube
  • ZD Surge arrester
  • ZE Glow modulator tube, a linear light source for rotating-drum FAX receivers, film soundtrack recording, etc.
  • ZF Flash tube
  • ZL Gas laser
  • ZM Cold cathode character display tube or counter display tube
  • ZP Radiation counter tube (Geiger-Müller counter tube or proportional counter tube)
  • ZQ Mixed analogue and digital display
  • ZR Plasma display panel
  • ZS Bar graph
  • ZT Thyratron
  • ZX Ignitron
  • ZY Mercury-vapor rectifier
  • ZZ Voltage stabilizer or corona discharge tube

Then follows a 4-digit sequentially assigned number.

Optional suffixes for camera tubes:

Version letter:

• B Blue
• G Green
• L Luminance
• R Red
• T Reticule
• X Medical X-ray

Letter for variants derived by selection:

• D High resolution
• M Blemish standard

For examples see below

Transmitting tubes

The first letter (or letter pair, in the case of a dual-system device) indicates the general type:

• B Backward-wave amplifier
• D Rectifier, including grid-controlled types
• J Magnetron
• K Klystron
• L Traveling-wave tube
• M Triode (AF amplifier or modulator)
• P Pentode
• Q Tetrode
• R Rectifier
• T Triode (AF, RF, oscillator)
• X Large thyratron (including all hydrogen thyratrons and high-current types)

The following letter indicates the filament or cathode type. The coding differs between Philips (and other Continental European manufacturers) on the one hand and its Mullard subsidiary on the other.

Philips system:

• A
  • Backward-wave amplifier or Traveling-wave tube: Output power <1W
  • Other tubes: Directly heated tungsten filament
• B
  • Backward-wave amplifier or Traveling-wave tube: Output power ≥1W
  • Other tubes: Directly heated thoriated tungsten filament
• C Directly heated oxide-coated filament
• D Disc-seal construction
• E Indirectly heated oxide-coated cathode

Mullard system:

• G Directly heated oxide-coated filament (only mercury-vapor rectifiers)
• V Indirectly heated oxide-coated cathode
• X Directly heated tungsten filament
• Y Directly heated thoriated tungsten filament
• Z Directly heated oxide-coated filament (except mercury-vapor rectifiers)

A different nomenclature applies to gas-filled devices, where the code indicates the type of filling:

• G Mercury-vapor filling
• H Hydrogen filling
• R Inert-gas filling
• X Xenon filling

The next letter indicates the cooling method or other significant characteristic:

• H Helix or other integral cooler
• L Forced-air cooling
• Q Shield-grid (tetrode) thyratron (thyratrons only)
• S Silica envelope, to allow for a glowing anode
• T Tunable microwave device
• W Water cooling

The following group of digits indicate:

• Microwave tubes: Frequency in GHz
• Rectifying tubes: DC output voltage in kV in a three-phase half-wave configuration
• Thyratrons: Peak inverse voltage in kV
• Transmitting tubes: Maximum anode voltage in kV

The following group of digits indicate the power:

• Backward-wave amplifier or Traveling-wave tube: Output power
  • 2nd letter: A - in mW
  • 2nd letter: B - in W
• Klystrons: Output power
• Magnetrons: Pulse output power in kW
• Continuously transmitting tubes: Maximum anode dissipation in W or kW in Class-C amplifier telegraphy
• Pulsed transmitting tubes: Maximum peak anode current in A (number preceded by "P")
• Rectifiers: Maximum average anode current in mA
• Thyratrons: Maximum average anode current:
  • Less than 3 digits: in mA
  • 3 or more digits:
    • 1st digit =0: in mA
    • 1st digit >0: in A

An optional following letter indicates the base or connection method:

• B Cables
• E Medium 7-pin base
• ED Edison screw lamp base
• EG Goliath base
• G Medium 4-pin base
• GB Jumbo 4-pin base
• GS Super jumbo 4-pin base
• N Medium 5-pin base
• P P-base

For examples see below

Phototubes and photomultipliers

The first digit indicates the tube base:

• 2 Loctal 8-pin base
• 3 Octal 8-pin base
• 5 Special base
• 8 Noval base
• 9 Miniature 7-pin base

The second digit is a sequentially assigned number.

The following letter indicates the photocathode type:

• A Caesium-activated antimony cathode. Used for reflective-mode photocathodes. Response range from ultraviolet to visible. Widely used.
• C Caesium-on-oxidated-silver cathode, also called S1. Transmission-mode, sensitive from 300–1200 nm. High dark current; used mainly in near-infrared, with the photocathode cooled.
• T Multialkali sodium-potassium-antimony-caesium cathode, wide spectral response from ultraviolet to near-infrared; special cathode processing can extend range to 930 nm. Used in broadband spectrophotometers.
• U Caesium-antimony cathode with a quartz window

The following letter indicates the filling:

• G Gas-filled
• V High-vacuum

A following letter P indicates a photomultiplier.

Examples

• 50AVP 11-stage photomultiplier for scintillation counters, duodecal base
• 51UVP 11-stage photomultiplier, duodecal base
• 52AVP/XP1180 10-stage photomultiplier, 13-pin base
• 53AVP, 153AVP 10-stage photomultiplier, diheptal 14-pin base
• 53UVP 11-stage photomultiplier, diheptal 14-pin base
• 54AVP 11-stage photomultiplier, diheptal 14-pin base
• 55AVP 15-stage photomultiplier, bidecal 20-pin base
• 56AVP 14-stage photomultiplier, bidecal 20-pin base
• 56UVP 14-stage photomultiplier, duodecal base
• 57AVP 11-stage photomultiplier, bidecal 20-pin base
• 58AVP 14-stage photomultiplier, bidecal 20-pin base
• 150AVP 10-stage photomultiplier, bidecal 20-pin base
• 150CVP 10-stage photomultiplier, bidecal 20-pin base
• 57CV Photometric cell
• 58CG Gas-filled phototube, Red/IR sensitive, all-glass pigtailed
• 58CV Vacuum phototube, Red/IR sensitive, all-glass pigtailed
• 90AG Gas-filled phototube, daylight/blue sensitive, miniature 7-pin base
• 90AV Vacuum phototube, blue sensitive, miniature 7-pin base
• 90CG Gas-filled phototube, Red/IR sensitive, miniature 7-pin base
• 90CV Vacuum phototube, Red/IR sensitive, miniature 7-pin base
• 92AG Gas-filled phototube, blue sensitive, miniature 7-pin base
• 92AV Vacuum phototube, blue sensitive, miniature 7-pin base
• 61SV/7634 PbS infrared (300...3500 nm) photoresistor, 2-pin all-glass pigtailed

Voltage stabilizers

The first number indicates the burning voltage

The following letter indicates the current range:

• A max. 10mA
• B max. 22mA
• C max. 40mA
• D max. 100mA
• E max. 200mA

The following digit is a sequentially assigned number.

An optional, following letter indicates the base:

• E Edison screw lamp base
• K Octal 8-pin base
• P P-base

Examples

• 75B1 Voltage reference tube, miniature 7-pin base
• 75C1 Voltage reference tube, miniature 7-pin base
• 83A1 Voltage reference tube, miniature 7-pin base
• 85A1/0E3 Voltage reference tube, Loctal B8G base
• 85A2/0G3 Voltage reference tube, miniature 7-pin base
• 90C1 Voltage reference tube, miniature 7-pin base
• 95A1 Voltage reference tube, miniature 7-pin base
• 100E1 Voltage reference tube, "A" Base
• 108C1/0B2 Voltage reference tube, miniature 7-pin base
• 150A1 Voltage reference tube, "P" base
• 150B2 Voltage reference tube, miniature 7-pin base
• 150B3 Voltage reference tube, miniature 7-pin base
• 150C1 Voltage reference tube, "P" base
• 150C2/0A2 Voltage reference tube, miniature 7-pin base
• 150C4 Voltage reference tube, miniature 7-pin base

Marconi-Osram system

The British Marconi-Osram designation from the 1920s uses one or two letter(s) followed by two numerals and sometimes by a second letter identifying different versions of a particular type.

The letter(s) generally denote the type or use:

• A General professional tube
• B Dual triode
• D Detector diode
• GU Gas-filled rectifier
• GT Gas-filled triode
• H High-impedance signal triode
• KT Kinkless Tetrode - beam power tube
• L Low-impedance signal triode
• MU Indirectly heated rectifier
• N Power pentode
• P Power triode
• QP Dual pentode
• S Tetrode
• U Rectifier
• VS Remote-cutoff tetrode
• W Remote-cutoff pentode
• X Triode/hexode frequency-changer
• Y Optical tuning/level indicator
• Z Sharp-cutoff RF pentode

The following numbers are sequentially assigned for each new device.

Examples:

Note: Kinkless Tetrode beam power tubes are listed under other letter tubes - KT

• A1834 = 6AS7G/ECC230 = CV2523 - Dual power triode (series regulator), octal base.
• B719 = 6AQ8/ECC85 - Dual RF triode, RF Amp & Mixer in FM receivers, 9-pin noval base.
• D41 = V914 - Indirectly heated, Double Detector Diode, British 5-pin base.
• D42 - Indirectly heated, Single Detector Diode, British 4-pin base.
• GU21 = AH221 = RG4-1250 - Half-wave mercury-vapor rectifier, Edison screw lamp base.
• H63 = 6F5 - Hi-mu triode, octal base.
• H610 - Directly heated, high-mu AF triode, British 4-pin base.
• L63 = 6J5 - Low-mu triode, octal base.
• L610 - Directly heated, Low-mu RF triode, British 4-pin base.
• MT7A, MT7B - Large radiation-cooled transmitting triodes used in the 1920s and 1930s.
• MU14 = UU5 = IW4-500 - Indirectly heated full-wave rectifier, British 4-pin base.
• N77 = 6AM5/EL91 - Power pentode, 7-pin miniature base.
• P610 - Directly heated, AF power triode, British 4-pin base.
• P625 - AF power triode.
• PX4 - AF power triode designed in the 1930s. Capable of providing about 4.5 W of audio.
• QP21 - Directly heated, dual AF (push-pull) power pentode, British 7-pin base.
• QP240 - Directly heated, dual AF (push-pull) power pentode, British 9-pin base.
• S610 - Directly heated, Sharp-cutoff RF tetrode, British 4-pin base.
• U52 = 5U4G = 5AS4A/5U4GB - Full-wave rectifier, octal base.
• VS24 - Directly heated, Remote-cutoff RF tetrode, British 4-pin base.
• W727 = 6BA6/EF93 = 5749 - Remote-cutoff RF pentode, 7-pin miniature base.
• X41 - Triode/hexode mixer designed to be a direct plug-in replacement for the MX40 pentagrid converter.
• X61, X61M = 6J8G - British triode/heptode mixer, octal based.
• X63 = 6A8 - Heptode pentagrid converter, octal based.
• X727 = 6BE6/EK90 = 5750 - Pentagrid converter, 7-pin miniature base.
• Y61, Y63 = 6U5G = VI103 - Optical tuning/level indicator, octal base, similar to 6G5.
• Z77 = 6AM6/EF91 - Sharp-cutoff RF pentode, 7-pin miniature base.

Mazda/Ediswan systems

Older system

First letter: Heater or filament voltage

• A 1 V
• B 2 V
• D 4 V
• E 5 V
• F 6 V
• G 7 V

Second letter: Heater or filament current

• W ≥200 mA
• X 150 mA
• Y 100...140 mA
• Z 50 mA

Next number: Gain

Next number: Internal resistance in kΩ

Signal tubes

First number: Heater or filament rating

• 0 Misc. higher voltages
• 1 1.4 V
• 6 6.3 V
• 10 100 mA
• 20 200 mA
• 30 300 mA

Following letter or letter sequence: Type

• C Frequency changer with special oscillator section
• D Signal diode(s)
• F Tetrode or pentode
• FD Tetrode or pentode and diode(s)
• FL Tetrode or pentode, and triode
• K Small gas triode or tetrode thyratron
• L Single or dual triode, including oscillator triode
• LD Triode and diode(s)
• M Optical tuning/level indicator
• P Power tetrode or pentode
• PL Power tetrode or pentode, and signal triode

Final number: Sequentially assigned number

Power rectifiers

Letter(s): Type

• U High-vacuum half-wave rectifier
• UU High-vacuum full-wave rectifier

Number: Sequentially assigned number

Examples:

Note: "AC/"-series receiver tubes are listed under other letter tubes - AC/

• 6C10 (6CU7/ECH42) Triode/hexode frequency converter, 8-pin Rimlock base
• 6F22 (6267/EF86) Low-noise A.F. pentode, 9-pin noval base
• 6F33 Shielded pentode, 7-pin base
• 6L12 (6AQ8/ECC85) Dual triode, 9-pin noval base
• 6L19 Dual triode, 8-pin base
• 6M2 (6CD7/EM34) Dual-sensitivity tuning indicator, 8-pin octal base
• 6P9 (6BM5) Power pentode, 7-pin base
• 6P15 (6BQ5/EL84) Power pentode, 9-pin noval base
• 10PL12 (50BM8/UCL82) Triode/power pentode, 9-pin noval base
• U381 (38A3/UY85) Half-wave rectifier, 9-pin noval base
• UU9 (6BT4/EZ40) Full-wave rectifier, 8-pin rimlock base

Standard Telephones and Cables/Brimar receiving tubes system

First number: Type

• 1 Half-wave rectifier
• 2 Diode
• 3 Power triode
• 4 High-mu triode
• 5 Sharp-cutoff tetrode
• 6 Vari-mu tetrode
• 7 Power or video pentode
• 8 Sharp-cutoff RF pentode
• 9 Vari-mu RF pentode
• 10 Dual diode
• 11 Triode and dual diode
• 12 AF Pentode and dual diode
• 13 Dual high-mu triode
• 14 Dual Class-B power triode
• 15 Heptode
• 16 DC-coupled power triode
• 17 RF pentode and dual diode
• 18 Pentode and triode
• 20 Hexode/heptode and triode

Next letter: Heater rating

• A 3.6 to 4.4V Indirectly heated
• B 2V Directly heated
• C Directly heated other than 2 or 4 V
• D All other heater ratings, indirectly heated other than 4V

Number: Sequentially assigned number

Examples:

• 1D6 Indirectly heated, half-wave rectifier, 5-pin base
• 4D1 Indirectly heated triode, 7-pin base
• 7A3 Indirectly heated power pentode, 7-pin base
• 8A1 Indirectly heated RF sharp-cutoff pentode, 5-pin base with anode top cap
• 9A1 Indirectly heated RF/IF remote-cutoff pentode, 5-pin base with anode top cap
• 10D1 Indirectly heated, common-cathode dual diode, 5-pin base
• 11A2 Indirectly heated, common-cathode dual diode and triode, 7-pin base
• 13D3 Indirectly heated, common-cathode dual triode, 9-pin base
• 15A2 Indirectly heated, heptode pentagrid converter, 7-pin base
• 20D4 Indirectly heated, triode/heptode frequency mixer, 9-pin base

Tesla receiving tubes system

First number: Heater voltage, as in the RETMA scheme

Next letter(s): Type, subset of the Mullard-Philips scheme

Next digit: Base

• 1 Octal K8A, A08
• 2 Loctal W8A
• 3 Miniature 7-pin B7G
• 4 Noval B9A
• 5 Special, mostly 9 out of 10 1.25mm pins on a 25mm-diameter circle
• 6 Submagnal B11A
• 7 Duodecal B12A
• 8 Diheptal B14A
• 9 Pigtails

Last digit: Sequentially assigned number

Examples:

• 1M90 (DM70/1M3) Subminiature indicator tube, 1.4V/25 mA filament, all-glass pigtailed
• 4L20 Directly heated RF power pentode; filament 2x 2.4V/325mA; Soviet 4П1Л, German RL4,2P6 with Loctal base
• 6B31 Dual diode up to 700 MHz; 6.3V/300mA heater, miniature 7-pin base
• 6BC32 (6AV6, EBC91) Dual diode and triode; 6.3V/300mA heater, miniature 7-pin base
• 6CC31 (6J6, ECC91) 600 MHz dual triode; 6.3V/450mA heater, miniature 7-pin base
• 6CC42 (2C51) VHF dual triode; 6.3V/350mA heater, noval base
• 6F24 Telecom pentode, 6.3V/450mA heater, Loctal base
• 6F36 (6AH6) Sharp-cutoff IF/video pentode, 6.3V/450mA heater, miniature 7-pin base
• 6H31 (6BE6, EK90) Heptode mixer; 6.3V/300mA heater, miniature 7-pin base
• 6L36 (6AQ5, EL90) Power pentode, 6.3V/450mA heater, miniature 7-pin base
• 6L41 (5763) Beam tetrode, 6.3V/750mA heater, noval base
• 35Y31 Half-wave rectifier, miniature 7-pin base; 35V/150mA series heater; UY1N with 7-pin base

Japanese Industrial Standards system

First letter: Base

• B Special
• D Subminiature
• G Octal
• L Loktal
• M Miniature 7-pin
• N Nuvistor
• R Noval 9-pin
• T Large 7-pin
• W 7-pin
• X 4-Pin
• Y 5-Pin
• Z 6-Pin

Second letter: Type

• A Power triode
• B Beam tetrode
• D Detector diode
• E Optical indicator
• G Gas-filled rectifier
• H Signal triode, gain < 30
• K Kenotron
• L Signal triode, gain > 30
• P Power pentode
• R Sharp-cutoff tetrode or pentode
• V Remote-cutoff tetrode or pentode

Number: Sequentially assigned number

• Rectifiers:
  • Even number: Full-wave
  • Odd number: Half-wave

Russian systems

Main article: Russian tube designations

Vacuum tubes produced in the former Soviet Union and in present-day Russia are designated in Cyrillic. Some confusion has been created in transliterating these designations to Latin.

Standard tubes

In the 1950s a 5-element system (GOST 5461-59, later 13393-76) was adopted in the (then) Soviet Union for designating receiver vacuum tubes.

The 1st element is a number specifying filament voltage in volts (rounded off to the nearest whole number), or, for cathode-ray tubes, the screen diagonal or diameter in cm (rounded-off to the nearest whole number).

The 2nd element is a Cyrillic character specifying the type of device:

• D (Russian: Д) - Diode, including damper diodes
• H (Russian: Х) - Double diode
• Ts (Russian: Ц) - Low-power rectifier (kenotron)
• S (Russian: С) - Triode
• N (Russian: Н) - Double triode
• E (Russian: Э) - Tetrode
• P (Russian: П) - Output pentode, or a beam tetrode
• Zh (Russian: Ж) - Sharp-cutoff pentode (also transliterated sh or j)
• K (Russian: К) - Variable-mu / remote-cutoff pentode
• R (Russian: Р) - Double pentode or a double tetrode
• G (Russian: Г) - Combined triode-diode
• B (Russian: Б) - Combined diode-pentode
• F (Russian: Ф) - Combined triode-pentode
• I (Russian: И) - Combined triode-hexode, triode-heptode or triode-octode
• A (Russian: А) - Pentagrid converter
• V (Russian: В) - Vacuum tube with secondary emission
• L (Russian: Л) - Cathode-ray tube
• Ye (Russian: Е) - Optical tuning/level indicator

The 3rd element is a number - a series designator that distinguishes between different devices of the same type.

The 4th element denotes vacuum tube construction (base, envelope):

• <none> - All-metal tube
• P (Russian: П) - Small 9-pin or 7-pin glass envelope (22.5 or 19 mm in diameter)
• A (Russian: А) - Subminiature glass envelope (5 to 8 mm in diameter) with flexible leads
• B (Russian: Б) - Subminiature glass envelope (8 to 10.2 mm in diameter) with flexible leads
• S (Russian: С) - Glass envelope (greater than 22.5 mm in diameter), typically with an octal base
• N (Russian: Н) - Nuvistor
• K (Russian: К) - Metal-ceramic envelope
• D (Russian: Д) - Glass-metal envelope with disc connections (for UHF operation)

The 5th element is optional. It consists of a dash ("-") followed by a single character or a combination of characters, and denotes special characteristics (if any) of the tube:

• V (Russian: В) - Increased reliability and mechanical ruggedness (such as low susceptibility to noise and microphonics)
• R (Russian: Р) - Even better than V
• Ye (Russian: Е) - Extended service life
• D (Russian: Д) - Exceptionally long service life
• I (Russian: И) - Optimised for "pulsed" (i.e. switching) mode of operation

Note: In most cases this means construction differences to the basic version, rather than a selection for those characteristics from the regular-quality production at the factory.

For examples see below

Very-high power tubes

There is another designation system for high-power tubes such as transmitter ones.

The 1st element is always G (Russian Г, for "генераторная" "generator").

The 2nd element (with some notable exceptions such as the Г807) is:

• K (Russian: К) - Shortwave tube (≤25 MHz)
• U (Russian: У) - VHF tube (25-600 MHz)
• S (Russian: С) - UHF tube (>600 MHz)
• M (Russian: М) - Modulator tube
• I (Russian: И) - Impulse tube

The 3rd element consists of a dash ("-") followed by the design serial number:

• A (Russian А) - Water-cooled
• B (Russian Б) - Air-cooled

For examples see below

Very-high power tubes designation (Eitel McCullough and derivatives)

Manufacturers of very-high power tubes use the following code:

• An initial digit denoting the number of electrodes:
  • 3 Triode
  • 4 Tetrode
  • 5 Pentode
• One optional letter denoting the construction type:
  • <none> Glass envelope
  • C Ceramic envelope
• One optional letter denoting the cooling method:
  • V Vapor cooled (anode is immersed in boiling water, and the steam is collected, condensed and recycled)
  • W Water cooled (water is pumped through an outer metal jacket thermically connected to the anode)
  • X Air cooled (air is blown through cooling fins thermically connected to the anode)
• A number to indicate the maximum anode dissipation in watts. This can be exceeded for a short time, as long as the average is not exceeded over the anode's thermal time constant (typically 0.1 sec). In Class-C applications, the amplifier output power delivered to the load may be higher than the device dissipation
• One or more manufacturer-proprietary letters denoting the construction variant
• An optional proprietary digit denoting the gain group

Examples:

• 3CW5000A3 5 kW Ceramic triode, water cooled, variant 'A', gain group 3
• 3CX100A5 100 W Ceramic UHF triode, forced-air cooled, variant 'A', gain group 5; often used by radio amateurs for 23cm-band microwave amplifiers.
• 3CX1500A7 (8877) 1.5 kW Ceramic triode, forced air cooled, variant 'A', gain group 7
• 3CX2500A3 2.5 kW Ceramic triode, forced air cooled, variant 'A', gain group 3
• 4-65A (8165) 65 W Glass beam tetrode
• 4-125A (4D21, 6155) 125 W Glass beam tetrode
• 4-250A (5D22, 6156) 110 MHz, 250 W Glass beam tetrode
• 4-400A 400 W Glass beam tetrode
• 4-1000A (8166) 1 kW Glass beam tetrode popular in broadcast and amateur transmitters.
• 4CX250B 250 W Ceramic tetrode, forced-air cooled, version 'B', favored by radio amateurs as a final amplifier.
• 4CX250DC 250 W Ceramic tetrode, forced-air cooled, version 'DC'
• 4CX35000 Ceramic tetrode used in numerous 50-kW broadcast transmitters, forced-air cooled, often in a Doherty configuration as in the Continental Electronics 317C series.
• 5-125B/4E27A 75 MHz, 125 W Glass power pentode
• 5-500A 500 W Glass radial-beam pentode
• 5CX1500A 110 MHz, 1.5 kW Ceramic radial-beam pentode, forced air cooled
• 5CX3000A 150 MHz, 4.0 kW Ceramic radial-beam pentode, forced air cooled

ETL computing tubes designation

The British Ericsson Telephones Limited (ETL), of Beeston, Nottingham (not to be confused with the Swedish TelefonAB Ericsson), original holder of the now-generic trademark Dekatron, used the following system:

• An initial letter denoting the filling:
  • G Gas-filled
  • V Vacuum

• One letter denoting the type:
  • C Common-cathode Counter Dekatron that makes only carry/borrow cathodes separately available for cascading
  • D Diode, voltage reference, etc.
  • R Register (Readout) - Digital indicator
  • S Separate-cathode Counter/Selector Dekatron that makes all cathodes available on individual pins for displaying, divide-by-n counter/timer/prescalers, etc.
  • TE Trigger tetrode, one starter electrode and a keep-alive (primer) electrode for ion availability
  • TR Trigger triode, one starter electrode only

• A digit group:
  • Dekatrons: Stage count
  • Digital indicators: Display cathode count
  • Diodes, voltage references: Nominal voltage
  • Trigger tubes: Ignition voltage

• An optional digit group after a slash: Pin count

• One letter denoting the type:
  • A Plastic base
  • B Plastic base
  • C Plastic base
  • D Plastic base
  • E Plastic base
  • G 26-pin B26A base
  • H 27-pin B27A base
  • M B7G base
  • P B7G base
  • Q B7G base
  • W Pigtails
  • X Pigtails
  • Y Pigtails

For examples see below under GC, GD, GR, GS, GTE, GTR and VS

Military naming systems

British CV naming system

This system prefixes a three- or four-digit number with the letters "CV", meaning "civilian valve" i.e. common to all three armed services. It was introduced during the Second World War to rationalise the previous nomenclatures maintained separately by the War Office/Ministry of Supply, Admiralty and Air Ministry/Ministry of Aircraft Production on behalf of the three armed services (e.g. "ACR~", "AR~", "AT~", etc. for CRTs, receiving and transmitting valves used in army equipments, "NC~", "NR~" and "NT~" similarly for navy equipments and "VCR~", "VR~" and "VT~" etc. for air force equipments), in which three separate designations could in principle apply to the same valve (which often had at least one prototype commercial designation as well). These numbers generally have identical equivalents in both the North American, RETMA, and West European, Mullard-Philips, systems but they bear no resemblance to the assigned "CV" number.

Examples

• CV1986 = 6SN7 = ECC33
• CV4007 = SQ version of 6AL5 = E91AA
• CV4010 = SQ version of 6AK5 = E95F

Note: The 4000 numbers identify special-quality valves.

The principle behind the CV numbering scheme was also adopted by the US Joint Army-Navy JAN numbering scheme which was later considerably expanded into the US Federal and then NATO Stock Number system used by all NATO countries. This part-identification system ensures that every particular spare part (not merely thermionic valves) receives a unique stock number across the whole of NATO irrespective of the source, and hence is not held inefficiently as separate stores. In the case of CV valves, the stock number is always of the format 5960-99-000-XXXX where XXXX is the CV number (with a leading 0 if the CV number only has 3 digits).

U.S. naming systems

One system prefixes a three-digit number with the letters "VT", presumably meaning "Vacuum Tube". Other systems prefix the number with the letters "JHS" or "JAN". The numbers following these prefixes can be "special" four-digit numbers, or domestic two- or three-digit numbers or simply the domestic North American "RETMA" numbering system. Like the British military system, these have many direct equivalents in the civilian types. Confusingly, the British also had two entirely different "VT" nomenclatures, one used by the Royal Air Force (see the preceding section) and the other used by the General Post Office, responsible for post and telecommunications at the time, where it may have stood for "valve, telephone"; none of these schemes corresponded in any way with each other.

Examples

• "VT" numbering systems
  • North American VT90 = 6H6
  • British (RAF) VT90 VHF Transmitting triode
  • British (GPO) VT90 = ML4 = CV1732 Power triode
  • VT104 RF pentode
  • VT105 RF triode

Other numeral-only systems

Various numeral-only systems exist. These tend to be used for devices used in commercial or industrial equipment.

For examples, see below

The oldest numbering systems date back to the early 1920s, such as a two-digit numbering system, starting with the UV-201A, which was considered as "type 01", and extended almost continuously up into the 1980s.

For examples see below

Three- and four-digit numeral-only systems were maintained by R.C.A., but also adopted by many other manufacturers, and typically encompassed rectifiers and radio transmitter output devices. Devices in the low 800s tend to be transmitter output types, those in the higher 800s are not vacuum tubes, but gas-filled rectifiers and thyratrons, and those in the 900s tend to be special-purpose and high-frequency devices. Use was not rigorously systematic: the 807 had variants 1624, 1625, and 807W.

For examples, see below under 800s, 900s and 1600s

Other letter followed by numerals

There are quite a number of these systems from different geographical realms, such as those used on devices from contemporary Russian and Chinese production. Other compound numbering systems were used to mark higher-reliability types used in industrial or commercial applications. Computers and telecommunication equipment also required valves (tubes) of greater quality and reliability than for domestic and consumer equipment.

Some letter prefixes are manufacterer's codes:

• C RCA/Cunningham
• CK, QK, RK Raytheon Company
• GE, GL General Electric Corp.
• EM Eitel McCullough
• F Federal Telephone and Radio
• HK Heintz & Kaufman, Ltd. (San Francisco, California, USA)
• HY CBS/Hytron
• ML Machlett Laboratories, Inc.
• NL National Electronics, Inc.
• NU National Union Electric Corp.
• PL Philips N.V.
• RCA RCA/Radiotron
• SV Svetlana/Светлана
• SY Standard Telephones and Cables Ltd./Brimar
• TH Thomson-CSF
• WL Westinghouse Electric Corp.
• XD Central Electronic Manufacturers (Denville, New Jersey, USA)

For examples, see below

Some designations are derived from the behavior of devices considered to be exceptional.

• Mazda sold their first tubes for 4-volts AC mains transformer (as opposed to home storage battery) heating with the prefix AC/ (for examples see below).
• The first beam tetrodes manufactured in the UK in the late 1930s by M-OV, carried a "KT" prefix meaning Kinkless Tetrode (for examples see below).

List of American RETMA tubes, with European equivalents

Note: Typecode explained above. See also RETMA tube designation

"0 volt" gas-filled cold cathode tubes

First character is numeric zero, not letter O.

• Voltage stabilisers and references. Function in a similar way to a Zener diode, at higher voltages. Letter order (A-B-C) indicates increasing voltage ratings on octal-based regulators and decreasing voltage ratings on miniature-based regulators.
  • 0A2 150 volt regulator, 7-pin miniature base
  • 0A3 75 volt regulator, octal base, aka VR75
  • 0B2 105 volt regulator, 7-pin miniature base
  • 0B3 90 volt regulator, octal base, aka VR90
  • 0C2 75 volt regulator, 7-pin miniature base
  • 0C3 105 volt regulator, octal base, aka VR105
  • 0D3 150 volt regulator, octal base, aka VR150
• Other cold-cathode tubes
  • 0A4G 25 mA_avg, 100mA_peak Gas triode designed for use as a ripple control receiver; with the cathode tied to the midpoint of a series-resonance LC circuit across live mains, it would activate a relay in its anode circuit while f_res is present
  • 0Y4 40 ≤ I ≤ 75 mA Half-wave gas rectifier with a starter anode, 5-pin octal base
  • 0Z4 30 ≤ I ≤ 90 mA Argon-filled, full-wave gas rectifier, octal base. Widely used in vibrator power supplies in early automobile radio receivers.

1 volt heater/filament tubes

• Tubes with 1.0 to 1.4 volt heaters
  • 1A3 High frequency diode with indirectly heated cathode. Used as a detector in some portable AM/FM receivers.
  • 1R5/DK91 Pentagrid converter, anode voltage in the 45-90 volt range.
  • 1S4 Power output pentode Class-A amplifier, anode voltage in the 45-90 volt range.
  • 1S5 Sharp-cutoff pentode Class-A amplifier, and diode, used as detector and first A.F. stage in battery radio receivers. Anode voltage in the 67-90 volt range. (B7G base)
  • 1T4 Remote-cutoff R.F. Pentode Class-A amplifier, used as R.F. and I.F. amplifier in battery radio receivers, similar characteristics to 6BA6 (B7G base).
  • 1U4 Sharp-cutoff R.F. Pentode Class-A amplifier, used as R.F. and I.F. amplifier in battery radio receivers, similar characteristics to 6BA6 (B7G base).
  • 1B3GT High-voltage rectifier diode common in monochrome TV receivers of the 1950s and early 1960s. Peak inverse voltage of 30 kV. Anode current 2 mA average, 17 mA peak. Derived from the earlier industrial type 8016. (International Octal base.)

• Tubes with 1.4 volt DC heaters
  • 1A7GT Pentagrid converter
  • 1G6-G Dual power triode. "GT" version also available.
  • 1LA6 (loctal) and later 1L6 (7-pin miniature) battery pentagrid converter for Zenith Trans-Oceanic shortwave radio
  • 1LB6 Superheterodyne mixer for battery-operated radios
  • 1LC6 Similar to type 1LA6, but with higher conversion transconductance
  • 1U6 Nearly identical to type 1L6, but with a 1.4 V/25 mA filament

1.25 volt filament subminiature tubes

The following tubes were used in post-WW2 walkie-talkies and pocket-sized portable radios. All have 1.25 volt DC filaments and directly heated cathodes. Some specify which end of the filament is to be powered by the positive side of the filament power supply (usually a battery). All have glass bodies that measure from 0.285 to 0.400 inches (7.24 mm to 10.16 mm) wide, and from 1.25 to 2.00 inches (31.75 mm to 50.4 mm) in overall length.

Those labeled 8 pin have round bodies and bases with 8 stiff pins arranged in a circle. Those marked FL have elliptical bodies and flat bases with long, inline "flying leads" that are soldered into the circuit. Those marked SL are similar to those marked FL, but have short inline leads that can be soldered or can be mated with a special socket. (Flying leads can be cut short to fit into inline sockets.)

• 1AC5 Power pentode, FL
• 1AD4 Sharp-cutoff pentode, FL
• 1AD5 Sharp-cutoff pentode, 8 pin
• 1AE5 Heptode mixer, FL
• 1AG4 Power pentode, FL
• 1AG5 Diode, pentode, FL
• 1AH4 RF pentode, FL
• 1AJ5 Diode, sharp-cutoff pentode, FL
• 1AK4 Sharp-cutoff pentode, FL
• 1AK5 Diode, sharp-cutoff pentode, FL
• 1C8 Pentagrid converter, 8 pin
• 1D3 Low-mu high-frequency triode, 8 pin
• 1E8 Pentagrid converter, 8 pin
• 1Q6 Diode, pentode, 8 pin
• 1S6 Diode, pentode, 8 pin
• 1T6 Diode, pentode, 8 pin
• 1V5 Power pentode, 8 pin
• 1V6 Triode-pentode converter, FL
• 1W5 Sharp-cutoff pentode, 8 pin

1 prefix for home receivers

These tubes were made for home storage battery receivers manufactured during the early to mid-1930s. The numbers of the following tubes all start with 1, but these tubes all have 2.0 volt DC filaments. This numbering scheme was intended to differentiate these tubes from the tubes with 2.5 volt AC heaters listed below.

• 1A4-p Remote-cutoff pentode
• 1A4-t Remote-cutoff tetrode
• 1A6 Pentagrid converter up to only 10 MHz due to low heater power (2 V/60 mA) and consequent low emission in the oscillator section; also occasionally used as a grid-leak detector
• 1A7-GT Re-engineered version of types 1A6 and 1D7-G, designed for use in portable AC/DC/Dry-cell battery radios introduced in 1938. Has 1.4 V/50 mA filament.
• 1B4-p Sharp-cutoff pentode
• 1B4-t Sharp-cutoff tetrode
• 1B5 Dual detector diode, medium-mu triode. Usually numbered 1B5/25S
• 1B7-GT Re-engineered version of types 1C6 and 1C7-G, designed for use in dry-cell battery radios with shortwave bands. Has 1.4 V/100 mA filament
• 1C5 Power pentode (similar to 3Q5 except for filament)
• 1C6 Pentagrid converter; 1A6, with double the heater power and double the frequency range
• 1C7-G Octal version of type 1C6.
• 1D5-Gp Octal version of type 1A4-p.
• 1D5-Gt Octal version of type 1A4-t. (Note: This is a shouldered "G" octal, not a cylindrical "GT" octal.)
• 1D7-G Octal version of type 1A6.
• 1E5-Gp Octal version of type 1B4-p.
• 1E5-Gt Octal version of type 1B4-t. (Note: This is a shouldered "G" octal, not a cylindrical "GT" octal.)
• 1E7-G Dual power pentode for use as a driver when parallel-connected, or as a push-pull output. "GT" version also available
• 1F4 Power pentode
• 1F5-G Octal version of 1F4.
• 1F6 Duplex diode, sharp-cutoff pentode
• 1F7-G Octal version of type 1F6
• 1G5-G Power pentode
• 1H4-G Medium-mu triode, can be used as a power triode. Octal version of type 30, which is an upgraded version of type 01-A. "GT" version also available.
• 1H6-G Octal version of type 1B5/25S. "GT" version also available.
• 1J5-G (950) AF Power pentode
• 1J6-G Dual power triode, octal version of type 19. "GT" version also available.

2 volt heater/filament tubes

• Tubes used in AC-powered radio receivers of the early 1930s. All have 2.5 volt heaters.
  • 2A3 Directly heated power triode, used for AF output stages in 1930s-1940s audio amplifiers and radios.
  • 2A5 Power Pentode (Except for heater, electronically identical to types 42 and 6F6)
  • 2A6 Dual diode, high-mu triode (Except for heater, electronically identical to type 75)
  • 2A7 Dual-tetrode-style pentagrid converter (Except for heater, electronically identical to types 6A7, 6A8 and 12A8)
  • 2B7 Dual diode and remote-cutoff pentode (Except for heater, electronically identical to type 6B7)
  • 2E5 and 2G5 Electron-ray indicators ("Eye tube") with integrated control triode. (Except for heater, electronically identical to types 6E5 and 6G5)

• Tubes used in television receivers
  • 2AF4 UHF triode oscillator
  • 2BN4 VHF/RF triode
  • 2CW4 Nuvistor high-mu VHF triode, 6CW4 with a 2.1 volt/450 mA heater
  • 2CY5 VHF sharp-cutoff RF tetrode
  • 2EA5 VHF sharp-cutoff RF tetrode
  • 2EN5 Dual-diode
  • 2ER5 VHF RF triode
  • 2ES5 VHF RF triode
  • 2EV5 VHF sharp-cutoff RF tetrode
  • 2FH5 VHF RF triode
  • 2FQ5 VHF RF triode
  • 2FV6 VHF sharp-cutoff RF tetrode
  • 2FY5 VHF RF triode
  • 2X2 High Vacuum High Peak inverse voltage diode, used as rectifier in CRT EHT supplies. Similar to 1B3 and 1S2 except for heater voltage.

5 volt heater/filament tubes

• 5AR4, GZ34 Full wave rectifier
• 5AS4 Full wave rectifier
• 5R4 Full wave rectifier
• 5U4 Full wave rectifier
• 5V4, GZ32 Full wave rectifier
• 5Y3 Full-wave rectifier, octal base version of type 80

6 volt heater/filament tubes

• 6A6 Dual Power Triode, used as a Class-A audio driver or a Class-B audio output. UX6 base. 6.3 volt heater version of type 53 which had a 2.5 volt heater. Octal version – 6N7.
• 6A7 and 6A8 (PH4, X63) Superheterodyne Pentagrid converter – dual tetrode style. Based on type 2A7, which had a 2.5 volt heater. 6A7 has a UX7 base with top cap connection for control grid (grid 4). 6A8 is octal version with top cap connection for control grid. Loctal version: type 7B8.
• 6AB4/EC92 High-mu triode (Pinout same as 6C4 except for pin 5 not having a connection)
• 6AB5/6N5 "Magic Eye" cathode ray tuning indicator
• 6AC5-G High-mu Power Triode
• 6AC7, 1852 TV sharp-cutoff R.F. Pentode. (Often encountered in a black metal envelope, not to be confused with the 6CA7.)
• 6AD6-G and 6AF6-G "Magic Eye" tuning indicators. Both have two "pie wedge" shadow indicators, one each on opposite sides of a single circular indicator target. Both shadows may be used in tandem or may be driven by two different signal sources. Type 6AE6-G is specifically made to drive each indicator with different signals. May also be driven by separate pentodes with different characteristics. E.g., a sharp-cutoff pentode like a 6J7 - which would be hyper-sensitive to any signal change—would drive one shadow, while a remote-cutoff pentode like a 6K7 - which would only react to stronger signals—would drive the other shadow. Both tubes have octal bases. Type 6AD6-G, with a target voltage rated from 100 to 150 volt, is designed for AC/DC radios. Type 6AF6-G, with a target voltage rated at 250 volt, is designed for larger AC radios.
• 6AE6-G A driver triode specially designed for "Magic Eye" tuning indicator types 6AD6-G and 6AF6-G. Has a common heater and indirectly heated cathode, two internally connected triode grids—one with sharp-cutoff characteristics, one with remote-cutoff characteristics—and two plates, one for each grid. The sharp-cutoff grid reacts to any signal change, while the remote-cutoff grid reacts only to stronger signal changes.
• 6AE7-GT Dual Triode with a common, single anode, for use as a power triode driver
• 6AF4 UHF Medium-mu Triode, commonly found in TV UHF tuners and converters.
• 6AG11 Compactron High-mu dual triode and dual diode
• 6AH5-G Beam power tube for early TV use. Same as type 6L6-G, but with scrambled pinout. Used in some Philco sets.
• 6AK5, EF95, 5654, CV4010, 6Ж1П Miniature V.H.F. Sharp-cutoff pentode (Used in old Radiosonde weather balloon transmitters, receiver front ends and contemporary audio equipment) B7G, (Miniature 7 pin) base
• 6AK6 Power pentode. 7-pin miniature version of type 6G6-G. Unusual low-power consumption output tube with 150 mA heater.
• 6AK8/EABC80 Triple Diode, High-mu Triode. Diodes have identical characteristics—two have cathodes connected to the triode's cathode, one has an autonomous cathode. Used as a combination AM detector/AVC rectifier/FM ratio detector/A.F. amplifier in AM/FM radios manufactured outside of North America. Triode amplification factor: 70. North American type 6T8 is identical (but for a shorter glass envelope) and may be used as a substitute.
• 6AL3, EY88 TV "Damper/Efficiency" Diode
• 6AL5, EAA91, D77 Dual Diode, Detector. Often used in vacuum tube volt meters (VTVMs). Miniature version of type 6H6.
• 6AL6-G Beam power tube for early TV use. Same as type 6L6-G, but with scrambled pinout and plate connected to top cap.
• 6AL7-GT Tuning indicator used in many early AM/FM Hi-Fi radios. Similar in function to "Magic Eye" tubes. Has two bar-shaped shadows; one grows to indicate signal strength, the other moves to indicate center tuning on FM.
• 6AM6, EF91, Z77, Sharp-cutoff R.F. pentode used in receiver front ends and test gear such as VTVMs and TV broadcast modulation monitors.
• 6AN7, ECH80 Triode-Hexode Local Oscillator/Mixer (radio)
• 6AQ5 Beam-power pentode, 7-pin miniature similar of type 6V6.
• 6AQ8 Dual Triode with internal shield, like 6BK7/6BQ7/6BZ7
• 6AR8, 6JH8, 6ME8 Beam deflection tubes for use as NTSC chroma signal demodulators in analog color TV receivers
• 6AS6 Pentode with a fine-pitched suppressor grid which could serve as a second control grid. Used in radar phantastron circuits.
• 6AS7, 6080 Dual low-mu Triode, low impedance, mostly used for voltage regulation circuits.
• 6AT6 Dual Diode, High-mu Triode, miniature version of type 6Q7. Triode amplification factor: 70.
• 6AU4 TV "Damper/Efficiency" Diode
• 6AU6, EF94, 6AU6A, Sharp-cutoff pentode
• 6AV6 Dual Diode, High-mu Triode, miniature version of type 75. Triode amplification factor: 100. (Triode section similar in characteristics to one half of a 12AX7.)
• 6AX4 TV "Damper/Efficiency" Diode
• 6AX5 Full-wave rectifier. Octal base. Similar in structure to type 6X5, but with higher voltage and current ratings which are comparable to those of types 5Y3 and 80.
• 6B6-G Double-Diode High-mu Triode. Octal version of type 75. Has top-cap connection for triode grid. Later octal version, type 6SQ7, has under-chassis connection for triode grid. Miniature version: 6AV6.
• 6B7 and 6B8 (EBF32): Double-Diode, Semiremote-cutoff Pentodes. Based on type 2B7 which had a 2.5 volt heater. Type 6B7 has a UX7 base with a top-cap connection for the control grid (grid 1). Type 6B8 has an octal base with a top cap. The diode plates are most commonly used as (second) detectors and AVC rectification in superheterodyne receivers. Because their control grids have both sharp-cutoff and remote-cutoff characteristics, these types were used as I.F. amplifiers with AVC bias to the control grid, and as A.F. amplifiers. These types were also used in reflex radios. In a typical 2B7/6B7/6B8 reflex circuit, the I.F. signal from the converter is injected into the pentode and is amplified. The diodes then act as detectors, separating the A.F. signal from the R.F. signal. The A.F. signal is then re-injected into the pentode, amplified, and sent to the audio output tube.
• 6BA6, EF93, W727, 5790 Semiremote-cutoff R.F. Pentode (Often encountered in car radios)
• 6BE6, EK90, 5750, X727 Pentagrid Converter (Often encountered in car radios)
• 6BF6 Dual Diode, Medium-mu triode. Miniature version of octal type 6R7.
• 6BG6 Beam tetrode, anode cap. Used in early TV magnetic-deflection horizontal-output stage.
• 6BK4 High Voltage beam Triode (30 kV anode voltage). Used as shunt regulator in color TV receivers and measurement equipment such as high voltage meters
• 6BK7 Dual Triode with Internal shield between each section, used in RF circuits (Similar to 6BQ7)
• 6BK8, EF86, Z729 Audio Pentode used in microphone preamplifiers and audiophile equipment
• 6BK11 Triple triode compactron preamplifier; used in some guitar amps made by Ampeg.
• 6BL8, ECF80 General-purpose Triode pentode used in TV, audio and test gear
• 6BM8, ECL82 Triode pentode used as the driver and output stages in audio amplifiers, audio output and vertical output stages in TV receivers and has even been seen in an electronic nerve stimulator.
• 6BN6 Gated-beam discriminator pentode, used in radar, dual channel oscilloscopes and F.M. quadrature detectors (cf. nonode)
• 6BQ5, EL84,(N709) 5.7 Watts AF Power pentode, noval base
• 6BQ6-GT Beam Power Pentode, used as a Horizontal Deflection Output tube in monochrome TV receivers of the 1950s. Most commonly used in receivers with diagonal screen sizes less than 19 inches (49 cm). (However, may be found in some larger models.) Larger receivers often used similar type 6DQ6. Later versions of this tube branded as 6BQ6-GTB/6CU6.
• 6BU8 Split Anode TV Sync Separator
• 6BX6, EF80, E80F (though not pin compatible) Sharp-cutoff R.F. Pentode (TV IF; E80F used in early computers.)
• 6BY6 Similar to type 6CS6, but with higher transconductance. 3BY6 with a different heater
• 6BY7, EF85, W719 Remote-cutoff R.F. Pentode (TV IF)
• 6BZ6 Sharp-cutoff R.F. pentode used in video I.F. circuits of the 1960s.
• 6BZ7 Dual Triode. See 6BK7
• 6C4 V.H.F. Triode
• 6C6 Sharp-cutoff R.F. Pentode. Most common commercial uses were as a tuned R.F. amplifier, a detector, and an A.F. amplifier. Also used in test equipment. Has UX6 base with top cap. Based on type 57, which had a 2.5 volt heater. Similar to types 1603, 77 and octal types 6J7 and 6SJ7.
• 6C10 Compactron High-mu triple triode - not related to the Edison/Swan (later Mazda) 6C10 triode-hexode
• 6CA4, EZ81 Full Wave Rectifier
• 6CA7, EL34 Audio Power Output Pentode
• 6CB6 Remote-cutoff R.F. Pentode used in video I.F. circuits of the 1950s and early 1960s.
• 6CG7 Dual Triode (used in TV and some audio amplifiers including modern solid-state designs often as a cathode follower, similar to 6SN7)
• 6CJ6 Line Output Pentode
• 6CL6 Power pentode
• 6CM5, EL36, EL360 Audio and TV Line Output Beam Power Tetrode.
• 6CW4 Nuvistor high-mu VHF triode
• 6D4 25 mA_avg, 100 mA_peak Indirectly heated, argon triode thyratron, negative starter voltage, miniature 7-pin base; found an additional use as a 0 to 10 MHz noise source, when operated as a diode (starter tied to cathode) in a transverse 375 G magnetic field. Sufficiently filtered for "flatness" ("white noise") in a band of interest, such noise was used for testing radio receivers, servo systems and occasionally in analog computing as a random value source.
• 6D6 Remote-Cutoff R.F. Pentode. Most common commercial uses were as an I.F. amplifier or as a superheterodyne mixer, aka 1st detector. Also used in test equipment. Has UX6 base with top cap. Based on type 58, which had a 2.5 volt heater. Similar to type 78. Octal version: 6U7-G.
• 6D8-G Superheterodyne Pentagrid converter, similar to type 6A8. Octal base with top cap. Has 150 mA heater. Used in pre-war 6-volt farm radios.
• 6DA6, EF89 R.F. Pentode used in AM/FM radios manufactured outside North America.
• 6DJ8, ECC88, E88CC, 6922, 6N23P, 6N11 Dual Audio and R.F. Triode (often used in TV broadcast equipment, test gear, oscilloscopes and audiophile gear) similar to 6ES8
• 6DQ6 Beam Power Pentode, used as a Horizontal Deflection Output tube in monochrome TV receivers of the 1950s. Most often found in receivers with diagonal screen measurements larger than 17 inches (43 cm). Smaller receivers often used similar type 6BQ6-GT. Also used as Audio Output tubes in Standel guitar amplifiers. Later versions branded as 6DQ6-B/6GW6.
• 6DR8, EBF83, R.F. pentode which will operate with 12 V anode supply, used as I.F. amplifier in car radios which run directly off the 13.5 volt supply.
• 6DS4 Nuvistor R.F. triode used in TV tuners immediately prior to the introduction of solid state tuning circuits. (RCA TVs equipped with a 6DS4 tuner bore the trademark "Nu-Vista Vision"); successor of the 6CW4.
• 6DS8, ECH83, Triode-Heptode Local oscillator-Mixer which will operate with 12 V anode supply, used in car radios which run directly off the 13.5 volt supply.
• 6DT6 Quadrature detector used in TV audio circuits of the 1950s and early 1960s.
• 6DV4 Medium-mu Nuvistor triode for UHF oscillators; some versions had a gold-plated envelope
• 6DX8 Triode pentode
• 6E5 "Magic Eye" Tuning indicator. Has incorporated driver triode with sharp-cutoff grid which makes it extremely sensitive to any changes in signal strength. Has UX6 base. Based on type 2E5, which had a 2.5 volt heater.
• 6EM5 TV Vertical Output Pentode
• 6ES6, EF98, R.F. pentode which will operate with 12 V anode supply, used as tuned R.F. amplifier in car radios which run directly off the 13.5 volt supply.
• 6ES8, ECC89, E89CC Dual Triode used as cascode R.F. amplifier in TV tuners and V.H.F. receiver front ends, also used as general-purpose dual triode in test gear, similar to 6DJ8
• 6F4 Acorn UHF triode up to 1.2 GHz, for use as an oscillator
• 6F5 High-mu triode, equal to triode section of type 6Q7
• 6F6, KT63 Power Pentode. Octal base version of type 42. Moderate power output rating—9 watts max. (Single-ended Class-A circuit); 11 watts max. (Push-pull Class-A circuit); 19 watts max. (push-pull Class-AB₂ circuit). Available in metal (numbered "6F6"), shouldered glass ("6F6-G"), and cylindrical glass ("6F6-GT"). Sometimes used as a transformer-coupled audio driver for types 6L6-GC and 807 when those tubes were used in Class-AB₂ or Class-B amplifiers. Also used as a Class-C oscillator/amplifier in transmitters.
• 6F7 Remote-cutoff Pentode, Medium-mu Triode. Has UX7 base with top-cap connection for the pentode's control grid (grid 1). Most common uses were as superheterodyne mixer ("first detector") and local oscillator, or as a combination I.F. amplifier (pentode) and (second) detector or A.F. amplifier (triode). Octal version: 6P7-G.
• 6FH8 Medium-mu triode and three-anode sharp-cutoff tetrode for use in TV receivers and complex wave generators
• 6G5 "Magic Eye" Tuning indicator. Has incorporated triode with remote-cutoff grid, which makes it less reactive to low-level changes in signal strength. Has UX6 base. Electronically identical to type 6U5 except for indicator. Both types had "pie wedge" shadow indicators. At first, the shadow indicator for type 6G5 was fully closed at zero signal and opened as signal strength increased. For type 6U5, the shadow indicator was fully open at zero signal and closed as signal strength increased. After World War II, type 6G5 was discontinued as a unique tube and all 6U5s were doubled branded either as 6G5/6U5 or 6U5/6G5.
• 6G6-G Power pentode. Octal base. Low power output—1.1 watt max. output. Has 150 mA heater. Used in pre-war 6-volt farm radios. Miniature version - 6AK6.
• 6G8-G Double-Diode Sharp-cutoff Pentode (Used as Detector and first A.F. stage in Australian 1940s radios)
• 6GK5 Miniature V,H.F. Triode (Used as V.H.F. local oscillator in some T.V. Turret Tuners)
• 6GM5 Beam power pentode, identical to 7591 and 7868 with a mini-noval pin base
• 6GV8, ECL85 Triode Pentode (TV vertical output)
• 6GW8, ECL86 Audio Triode Pentode (audio, TV vertical output)
• 6H6, D63, EB34, OSW3109. Dual Diode. Octal base. Most commonly found as a "stubby" metal envelope tube. Glass versions 6H6-G and 6H6-GT are also found.
• 6HS8 Dual-anode pentode for TV receiver sync separation service or as a two-channel VCA
• 6J5, L63. Medium-mu triode.
• 6J5WGT Heater cathode type, medium-mu triode, identical to 12J5WGT except heater characteristics
• 6J7, EF37. Sharp-cutoff Pentode. Most common commercial uses were as a tuned R.F. amplifier, a (second) detector, or an A.F. amplifier. Octal version of type 77. This type included a top-cap connection for the control grid. Later version, type 6SJ7, had its control grid connection on pin 4.
• 6J8-G Triode-Heptode (radio local oscillator/mixer)
• 6JU8A 9 mA, Four-diode bridge rectifier
• 6K6-G Power Pentode, octal version of type 41. Low-to-moderate power output rating—0.35 to 4.5 watts (single-ended Class-A circuit); 10.5 watts max. (push-pull Class-A circuit).
• 6K7, EF39. Remote-cutoff R.F. pentode. Most common commercial uses were as an I.F. amplifier or as a superheterodyne mixer, aka 1st detector. Also used in test equipment. Octal version of type 78. This type included a top-cap connection for the control grid. Later version, type 6SK7, had its control grid connection on pin 4.
• 6K8 and 12K8 – American Triode-Hexode mixer, 1938
• 6K11 Compactron Triple triode
• 6KM8 Diode and three-anode sharp-cutoff tetrode for use in musical instruments, frequency dividers and complex wave generators
• 6L4 Acorn UHF triode for use as an oscillator
• 6L5-G Medium-mu triode (Similar to type 6J5-G, available only in ST shape)
• 6L6/EL37 High-powered beam tetrode.

There are several variations. Except for types 6L6-GC and 6L6-GX, all have the same maximum output ratings:

• 11.5 watts (single-ended Class-A circuit)
• 14.5 watts (push-pull Class-A circuit)
• 34 watts (push-pull Class-AB₁ circuit)
• 60 watts (push-pull Class-AB₂ circuit)

6L6 (metal envelope) and 6L6-G (shouldered glass envelope) were used in pre-World War II radios and Public Address amplifiers.

6L6 and 25L6 were introduced in 1935 as the first beam tetrodes. Both types were branded with the L6 ending to signify their (then) uniqueness among audio output tubes. However, this is the only similarity between the two tubes. (Type 6W6-GT is the 6.3 volt heater version of types 25L6-GT and 50L6-GT.)

• 6L6GA Post-war version of type 6L6-G, in smaller ST-14 shape with Shouldered Tubular, (ST), shaped bulb, revision A.
• 6L6GB Post-war improved version in a cylindrical glass envelope. Similar to type 5881.

• 6L6GTB, Type 6L6 with Tubular, (T), shaped bulb, revision B, (higher power rating, as it happens. The 6L6GTB can always replace the 6L6, 6L6G, and 6L6GT, but a 6L6GTB running at maximum rating should not be replaced with another subtype).
• 6L6-WGB "Industrial" version of type 6L6GB.

• 6L6GC Final and highest-powered audio version of the tube. Max. outputs:

• 17.5 watts (single-ended Class-A circuit)
• 32 watts (push-pull Class-A circuit)
• 55 watts (push-pull Class-AB₁ circuit)
• 60 watts (push-pull Class-AB₂ circuit)

• 6L6-GX Class-C oscillator/amplifier used in transmitters. Max. output 30 watts. (All versions may be used as a Class-C oscillator/amplifier, but this version is specifically designed for this purpose, has a special ceramic base.)

• 6L7 Pentagrid converter often used in console radios of the late 1930s. Similar in structure to pentode-triode pentagrid converters 6SA7 and 6BE6, except that a separate oscillator—usually type 6C5 - is required. Also, grid 1 is remote-cutoff control grid, grid 3 is oscillator input grid. (In types 6SA7 and 6BE6, grid 1 is the internal oscillator grid, grid 3 is the control grid.) Because of low conversion transconductance, radios using type 6L7 typically have either a tuned RF pre-amplifier stage, or at least two stages of I.F. amplification. (A few models have both.)
• 6LF6 Beam power tetrode with a duodecar Compactron base and anode cap, for CRT horizontal-deflection amplifiers
• 6M5 Audio Output Pentode (Used as Class-A or C output stages of 1950s Australian radiograms) similar to 6BQ5
• 6M11 Compactron Dual triode and pentode
• 6ME4 Tuning indicator
• 6ME5 Tuning indicator
• 6ME10 Tuning indicator
• 6MDE1 Tuning indicator
• 6MK8 Dual-anode pentode for TV receiver sync separation service or as a two-channel VCA
• 6N3, EY82 Half-Wave Rectifier
• 6N5/6N5P Tuning indicator
• 6N7 Dual Power Triode, used as Class-A audio driver or as Class-B power output (also 6N7-G and 6N7-GT). Max. output (Class-B) - 10 watts. Octal version of type 6A6.
• 6N8, EBF80 Remote-cutoff pentode, dual diode. (detector plus RF or AF amplifier in radios)
• 6P5-G/GT Medium-mu triode, Octal version of type 76, often used as driver for type 6AC5-G.
• 6P7-G Rarely seen octal version of type 6F7.
• 6Q5-G Triode gas thyratron used in DuMont oscilloscopes as a sweep generator. Identical to RMA type 884.
• 6R3, EY81 TV "Damper/Efficiency" Diode
• 6R7 Dual Diode, Medium-mu Triode (also 6R7-G and 6R7-GT). Octal base with top cap. Miniature version - 6BF6. Amplification factor: 16.
• 6S7-G Remote-cutoff RF Pentode, similar to type 6K7. Octal base with top cap. Has 150 ms heater. Used in pre-war 6-volt farm radios.
• 6S8-GT Triple Diode, High-mu Triode. Octal tube with top-cap connection to triode grid. Has three identical diodes—two diodes share a cathode with the triode, one has an autonomous cathode. Used as a combined AM detector/AVC rectifier/FM ratio detector/A.F. amplifier in AM/FM radios. Typically, all sections of this tube are arranged around a single heater.
• 6SA7 First pentode-triode style pentagrid converter. Octal type. Miniature version: 6BE6.
• 6SB7Y (octal), 6BA7 and 12BA7 (9-pin miniatures) – VHF Pentagrids, 1946
• 6SC7 High-mu dual triode (Both sections share a single cathode)
• 6SK7 Remote-cutoff pentode (Used in I.F. stages of North American radios) Miniature version: 6BD6
• 6SL7, ECC35. Dual triode (Used in TV and general electronics)
• 6SN7, ECC32, B65, 13D2, CV1986, 6042? Medium-mu dual triode (Used in Audio Amplifiers, Hammond Organs and Television; extensive use in World War II radar) Each section is equivalent to a 6J5. Miniature version: 12AU7
• 6SS7 Remote-cutoff pentode (150 mA filament version of the 6SK7, found in some AA6 radios as both the RF amplifier and first IF). This is the only tube to have two of the same letters in its type.
• 6T5 "Magic Eye" Tuning indicator. Has incorporated driver triode with remote-cutoff grid. Has UX6 base. Shadow indicator is fully closed at zero signal. As signal increases, shadow grows outward from the center, covering the entire circumference of the indicator. Electronically identical to types 6G5 and 6U5, which may be used as substitutes.
• 6T7-G Dual diode, high-mu triode, similar to type 6Q7. Octal base with top cap. Has 150 mA heater. Used in pre-war farm radios.
• 6T8 Triple Diode, High-mu Triode. Has three identical diodes—two have cathodes connected to the triode's cathode, one has an autonomous cathode. Triode amplification factor: 70. Used as an AM detector/AVC rectifier/FM ratio detector/A.F. amplifier in North American AM/FM radios. Identical to type 6AK8/EABC80, but with a shorter glass envelope.
• 6U5 "Magic Eye" Tuning indicator. Has incorporated driver triode with remote-cutoff grid. Has UX6 base. Has "pie wedge" shadow indicator that is open at zero signal and closes as signal increases. Electronically identical to types 6G5 and 6T5 and may be used as a substitute for those types. After World War II, most new 6U5s were double-branded as either 6G5/6U5 or 6U5/6G5.
• 6U5G "Magic Eye" Tuning indicator with triode, International Octal, (IO), base
• 6U7-G Remote-cutoff R.F. Pentode. Most common commercial uses were as an I.F. amplifier or as a superheterodyne mixer, aka 1st detector. Also used in test equipment. Octal version of type 6D6. Most direct substitute: 6K7. Similar to types 58, 78 and 6SK7.
• 6U8A Split triode-pentode, mini-noval pinbase. Audio preamplifier.
• 6V6 Beam power tetrode, used in single-ended Class-A audio output stages of radios and sometimes seen in Class-B audio amplifiers (see also: 5V6 and 12V6). Electrically similar to 6AQ5/EL90.
  • 6V6G, Type 6V6 with Shouldered Tubular, (ST), shaped bulb.
  • 6V6GT, Type 6V6 with Tubular, (T), shaped bulb.
• 6V7-G, Dual Diode, Medium-mu Triode. Octal version of type 85. Amplification factor: 8.3. Similar to type 6R7.
• 6W6-GT Beam power pentode, used most often as a Vertical Deflection Output tube in monochrome TV receivers of the 1950s. Can also used as an Audio Output tube. This is the 6.3 volt heater version of types 25L6-GT and 50L6-GT.

• 6X4 (EZ90) and 6X5 (EZ35): Full-wave rectifiers with indirectly heated common cathode. Type 6X4 has a 7-pin miniature base, the 6X5 has an octal base. Based on type 84/6Z4. No longer in production.

"7" prefix loctal tubes

These tubes all have 6.3 volt AC/DC heaters.

• 7A4 Medium-mu triode, loctal version of type 6J5, often numbered 7A4/XXL
• 7A5 Beam power pentode, loctal version of type 6U6GT
• 7A6 Dual detector diode, similar to type 6H6
• 7A7 Remote-cutoff pentode, loctal version of type 6SK7
• 7A8 The only octode pentagrid converter produced in America by Sylvania, 1939. Used mostly in Philco radios.
• 7AB7 Sharp-cutoff pentode
• 7AD7 Power pentode
• 7AF7 Dual medium-mu triode
• 7AG7 Sharp-cutoff pentode
• 7AH7 Remote-cutoff pentode
• 7AJ7 Sharp-cutoff pentode
• 7AK7 Sharp-cutoff, dual control pentode for computer service. Perhaps the first active device specifically designed for computer use.
• 7B4 High-mu triode, loctal version of types 6F5 and 6SF5
• 7B5 Power pentode, loctal version of types 6K6 and 41
• 7B6 High-mu triode, dual detector diodes, loctal version of type 75, similar to types 6AV6 and 6SQ7
• 7B7 Remote-cutoff pentode
• 7B8 Pentagrid converter, loctal version of types 6A7 and 6A8
• 7C4 High frequency diode
• 7C5 Beam power pentode, loctal version of type 6V6
• 7C6 High-mu triode, dual detector diode
• 7C7 Sharp-cutoff pentode
• 7E5 Medium-mu high-frequency triode
• 7E6 Medium-mu triode, dual detector diode, loctal version of types 6R7 and 6SR7, electronically identical to miniature type 6BF6.
• 7E7 Semiremote-cutoff pentode, dual detector diode, similar to types 6B7 and 6B8
• 7F7 High-mu dual triode, loctal version of type 6SL7-GT
• 7F8 Medium-mu high-frequency triode, used as FM RF amplifier and converter
• 7G7 Sharp-cutoff pentode
• 7G8 Sharp-cutoff dual tetrode
• 7H7 Semiremote-cutoff pentode
• 7J7 Triode-heptode converter, similar to type 6J8-G
• 7K7 High-mu triode, dual detector diode, similar to types 6AT6 and 6Q7
• 7L7 Sharp-cutoff pentode
• 7N7 Dual medium-mu triode, loctal version of type 6SN7-GT
• 7Q7 Pentagrid converter, similar to type 6SA7
• 7R7 Remote-cutoff pentode, dual detector diode
• 7S7 Triode-heptode converter
• 7T7 Sharp-cutoff pentode
• 7V7 Sharp-cutoff pentode
• 7W7 Sharp-cutoff pentode
  • Note Types 7V7 and 7W7 are electronically identical except for base connections of pins 4, 5 and 7. On type 7V7, the suppressor grid (grid 3) is connected to pin 4, an internal shield is connected to pin 5, and the cathode is connected to pin 7. On type 7W7, the suppressor grid and internal shield are connected to pin 5, and the cathode is connected to pins 4 and 7. All other pin connections are the same. If interchanging these tube types is necessary, confirm that pins 4 and 7 are connected at the socket. (Pin 5 is usually connected to the chassis.)
• 7X6 Dual rectifier diode
• 7X7 High-mu triode, dual detector diodes on separate cathodes, used as FM discriminator and AF amplifier, often numbered 7X7/XXFM
• 7Y4 Dual rectifier diode
• 7Z4 Dual rectifier diode

12 volt heater/filament tubes

• 12A5 Power pentode. UX7 base. Single-section tube with two side-by-side 6.3 volt heater-cathode structures. Each is connected together to form (1) a 12.6 volt 300 mA heater for series heater strings, or (2) a 6.3 volt 600 mA heater for parallel heater circuits. Mostly used in pre-war car radios.
• 12A7 Power pentode, rectifier diode. Pentode section is similar to type 38. Diode has a low power rating—120 volt, 30 mA — that limits the number of tubes that can be tied to its B+ circuit. Used in one-tube portable phonographs and a few two- and three-tube radios. Forerunner of such types as 32L7-GT, 70L7-GT and 117L7-GT. UX7 base with top cap. Not related to types 2A7 and 6A7.
• 12AB5 Beam Power Tube,
• 12AE10 Compactron Beam power tube and sharp-cutoff pentode
• 12AL5 Dual diode (similar to 6AL5 except for heater)
• 12AT6 Dual diode/triode (Commonly replaced by 12AV6 in consumer radios)
• 12AT7, ECC81, 6060, B309, M8162 High-mu dual triode. Commonly used as R.F. amplifier/mixer in VHF circuits.
• 12AU7, ECC82, 6067, B329, M8136 Medium-mu dual triode. Two 6C4s in one envelope. Commonly used in audio applications and TV receivers
• 12AV6 Dual diode/High-mu triode (see also: 6AV6)
• 12AV7, 5965 Medium-mu dual triode. Principally designed for VHF amplifier/mixer operation.
• 12AX7, ECC83, 6057, B327, M8137 High-mu dual triode. Very similar to triode section of 6AV6. Commonly used in high-gain audio stages.
• 12AY7 Dual Triode. Medium gain but low noise, intended for low-level/preamplifier use.
• 12AZ7 Double Triode. Medium-mu, AF Amplifier, or combined oscillator and mixer, 9-pin
• 12B4A Low-mu triode, noval base
• 12BA6 Remote-cutoff pentode, 6BA6/EF93 with a different heater
• 12BE6 Pentagrid converter, 6BE6/EK90 with a different heater
• 12BH7 Dual Triode, Medium-mu, designed for use in equipment having series heater-string arrangement
• 12BY7 Video Amplifier Pentode
• 12DT6 Sharp-cutoff pentode
• 12DW7 Dissimilar triodes. One half 12AX7 value, other half 12AU7 value. (also known as 7247 or ECC832)
• 12EG6 Pentagrid converter, both grids 1 and 3 are sharp-cutoff, has 12.6 volt anode and screen grid voltage, for use with audio equipment powered by a car battery
• 12FA6 Low-anode voltage, car radio version of 12BE6 pentagrid converter
• 12FQ8 Common-cathode, dual split-anode triode for use in musical instruments, frequency dividers and complex wave generators
• 12FX8 Low-anode voltage, triode-heptode converter for car radios
• 12GA6 Similar to type 12FA6, but with lower conversion transconductance
• 12J5WGT Heater cathode type, medium-mu triode, identical to 6J5WGT except heater characteristics
• 12K5 Tetrode, one of a few tubes that can function with low plate voltages (See Space charge)
• 12SA7 Pentagrid converter (Octal version of 12BE6)
• 12SK7 Remote-cutoff Pentode (Octal version of 12BA6)
• 12SQ7 Dual diode, triode (Octal version of 12AV6)
• 12U5G Tuning indicator identical to 6U5G except heater characteristics
• 12Z3 Half-wave rectifier, UX4 base

"14" prefix loctal tubes

These tubes all have 12.6 volt AC/DC heaters

• 14A4 Medium-mu triode, loctal version of type 12J5
• 14A5 Beam power pentode
• 14A7 Remote-cutoff pentode, often numbered 14A7/12B7
• 14AF7 Dual medium-mu triodes, often numbered 14AF7/XXD
• 14B6 High-mu triode, dual detector diode, similar to types 12AV6 and 12SQ7
• 14B8 Pentagrid converter, loctal version of type 12A8
• 14C5 Beam power pentode, loctal version of type 12V6-GT
• 14C7 Sharp-cutoff pentode
• 14E6 Medium-mu triode, dual detector diode, loctal version of 12SR7
• 14E7 Semiremote-cutoff pentode, dual detector diode, similar to type 12C8
• 14F7 High-mu dual triode, loctal version of type 12SL7-GT
• 14F8 Medium-mu high frequency triode, used as FM RF amplifier and converter
• 14H7 Semiremote-cutoff pentode
• 14J7 Triode-heptode converter
• 14N7 Dual medium-mu triode, loctal version of type 12SN7-GT
• 14Q7 Pentagrid converter, similar to type 12SA7
• 14R7 Remote-cutoff pentode, dual detector diode
• 14S7 Triode-heptode converter
• 14W7 Sharp-cutoff pentode
• 14X7 High-mu triode, dual detector diodes on separate cathodes, used as FM discriminator and AF amplifier
• 14Y4 Dual rectifier diode

25 volt heater/filament tubes

• 25A6 Power pentode, octal version of type 43
• 25C5 Beam Power Pentode (Identical to the 50C5 but with a 25 V 300 mA filament)
• 25F5 Beam Power Pentode (Identical to the 50C5, but with a 25 V 150 mA filament, used in some AA5 type radios using push-pull output)
• 25L6 Beam-power pentode (Except for heater, electrically identical to type 50L6)
• 25Z5 Dual rectifier diode
• 25Z6 Octal version of 25Z5

35 volt heater/filament tubes

• 35A5 Beam Power Tube (Loctal, Similar to 35L6)
• 35B5 Beam power tube
• 35C5 Identical to 35B5 except for basing ("pin-out") arrangement (HL92)
• 35HB8 Triode/Beam Power tube (Used primarily as both the audio amplifier and output)
• 35DZ8 High-mu Triode/Beam Power tube (Like the 35HB8, used for audio)
• 35L6-GT Beam power pentode similar to, but not electronically identical to, types 25L6-GT and 50L6-GT
• 35W4 Rectifier diode
• 35Z4-GT Rectifier diode
• 35Z5-GT Similar to 35Z4-GT, but equipped with a heater tap used to power a pilot light
• 35Z3 Rectifier Diode (Loctal, Similar to 35Z4)
• 35Y4 Rectifier Diode (Loctal, similar to 35Z5)

50 volt heater/filament tubes

• 50B5 Beam power tube, similar to 35B5 but with 50 volt filament
• 50C5 Similar to 35C5 but with 50 volt filament, and 50B5 except for basing ("pin-out") arrangement (HL92)
• 50EH5 Beam Power tube, (Similar to 50C5 but with higher gain, some radios that use this tube do not have an audio amplifier section.)
• 50L6 Beam power tube (see also 25L6)
• 50HK6 Power pentode (Filament is tapped for use with a dial lamp)
• 50A5 Beam Power Tube (Loctal, similar to 50L6)
• 50X6 Dual Diode (Loctal, commonly used as a rectifier-doubler)
• 50DC4 Rectifier diode (Similar to 35W4 except for filament)

117 volt heater tubes

All of the following tubes are designed to operate with their heaters connected directly to the 117 volt (now 120 volt) electrical mains of North America. All of them use indirectly heated cathodes. All of them incorporate at least one rectifier diode.

• Rectifier diode – Beam power pentode combinations
  • 117L7GT
  • 117M7GT
  • 117N7GT
  • 117P7GT
• Rectifier tubes
  • 117Z3 Single diode, 7-pin miniature version of 117Z4GT
  • 117Z4GT
  • 117Z6GT Dual diode, can be used as a voltage doubler

Other tubes with nonstandard filament voltages

The tubes in this list are most commonly used in series-wired circuits.

• 4CB6 Sharp-cutoff pentode
• 7AU7 Medium-mu Dual triode with a tapped filament like its more common brother, the 12AU7. 7.0/3.5 V
• 7KY6 Sharp-cutoff frame-grid pentode with a 7.3 volt nominal heater voltage for use as video output tube in TV receivers, 9 pin miniature socket
• 8B10 Compactron Dual triode and dual diode
• 8FQ7/8CG7 Dual triode (8 V version of the common 6CG7)
• 10DE7 Dual triode (dissimilar triode sections)
• 11DS5 Beam Power tube (11 V filament version of the 50B5/35B5)
• 13CW4 Nuvistor used as a preamplifier in Neumann condenser microphones U-47 and U-48 after the production of the VF14 ceased
• 18FX6 Pentagrid converter (18 V version of the 12BE6)
• 18FY6 Dual diode/triode (18 V version of the 12AV6)
• 34GD5 Beam power tube (34 V version of the 35C5/50C5)
• 36AM3 Half-wave rectifier (36 V version of the 35W4)
• 38HE7 Compactron Diode and beam power tube
• 38HK7 Compactron Diode and beam power tube

List of EIA professional tubes

Note: Some manufacterers preceded the EIA number with a manufacterer's code, as explained above.

4000s

• 4065 Directly heated electrometer triode with a space charge grid, grid current ≤125 fA, 4-pin all-glass pigtail, for probe amplifiers
• 4205 Directly heated power triode, 4-pin bayonet base with offset pin
• 4270A (3C/350E) Directly heated power triode, 4-pin base
• 4275 Directly heated power triode, 4-pin base
• 4300 Directly heated power triode, 4-pin base
• 4613 Directly heated power triode, 4-pin base
• 4614 Indirectly heated power triode, 5-pin base
• 4641 Directly heated power triode, 4-pin base
• 4671/E1C (955) Indirectly heated Acorn triode
• 4672/E1F (954) Indirectly heated Acorn pentode
• 4674 Indirectly heated Acorn diode
• 4675 4671/E1C with a 4 Volts heater
• 4676 4672/E1F with a 4 Volts heater
• 4678 (EM1) Indirectly heated tuning indicator
• 4683 Directly heated power triode, 8-pin base
• 4695/E2F (956) Indirectly heated Acorn pentode

5000s

5651

• 5651 86-volts, cold-cathode, glow-discharge voltage reference, 7-pin miniature base
• 5678 (CK5678 Raytheon), 5 leads Subminiature shielded pentode for RF applications
• 5691 Special Red ruggedized long-life high-mu triode for industrial applications
• 5692 Special Red ruggedized long-life medium-mu triode for industrial applications
• 5693 Special Red ruggedized long-life sharp-curoff pentode for industrial applications
• 5654, 6AK5, EF95, CV4010, 62H1P, 408A VHF pentode; common in vintage radar IF amplifiers.
• 5704 Subminiature diode, all-glass pigtailed
• 5727 650 V, 100 mA_avg, 500 mA_peak, 10 A_surge Indirectly heated tetrode thyratron, positive starter voltage, miniature 7-pin base
• 5731 Narrow-tolerance selected 955 Acorn triode for use in Radiosonde weather balloon transmitters
• 5734 Mechano-electronic displacement sensor; a vacuum triode with its anode mounted on a shaft that extends through a thin, flexible metal diaphragm; shaft movement is reflected in anode current; F_res = 12 kHz
• 5749, 6BA6, EF93, W727 RF pentode
• 5750, 6BE6, EK90, X727 heptode mixer
• 5751 Low-voltage, low-noise avionics dual triode with separate cathodes
• 5814A Industrial, computer-rated version of 12AU7/ECC82
• 5845 Dual directly heated saturated-emission diode. Acts as a heating current-controlled, variable series resistor in voltage/current stabilizer circuits.
• 5965 Dual triode, designed for high speed digital computers, has a high zero-bias plate current, identical to 12AV7

6000s

• 6057, 12AX7, ECC83, M8137, B339 high-mu double triode
• 6059, 6BR7 Low-microphonics pentode
• 6060, 12AT7, ECC81, M8162, B309 high-mu double triode
• 6064, 6AM6, EF91, M8083, Z77 R.F. pentode
• 6067, 12AU7, ECC82, M8136, B329 medium-mu double triode
• 6080, 6AS7 Very-low impedance double triode, designed for series voltage regulator applications, now popular for output transformerless audio amplifiers
• 6090 Beam-deflection, 18-channel analog demultiplexer for telecomms receiving channel banks, internal electrostatic focusing and deflection to determine which one out of 18 anodes receives the electron beam controlled by a common grid. Complementary muxers at the transmitting end include the 6170 and the 6324
• 6146 60 MHz, 120 W Power AF/RF/VHF Beam pentode
• 6146B (8298A) Improved version of 6146, 6146A and 8298.
• 6170 and 6324 Beam-deflection, 25-channel analog multiplexer for telecomms transmitting channel banks, external focusing and deflection by a multiphase, rotating magnetic field to determine through which one out of 25 grids the electron beam passes to the common anode. Complementary demuxers at the receiving end include the 6090
• 6218/E80T (CV5724) Special quality, modulated, single-anode beam deflection tube for pulse generation up to 375 MHz; shock resistant up to 500 g
• 6361 Convectron, an inclinometer tube that senses tilt from the vertical by means of different gas convections around a heating wire in a glass envelope, of two 6361s aligned in a 90° V-shaped position to each other and the heating wires connected in a bridge circuit
• 6550 20 W AF beam tetrode for high fidelity amplifiers
• 6700 200 ns Decade counter Magnetron Beam Switching Tube, 6.3 V, 300 mA heater
• 6701 Low-voltage 500 ns decade counter Magnetron Beam Switching Tube, 6.3 V, 300 mA heater
• 6710 2 MHz Decade counter Beam-X Switch, 6.3 V heater
• 6846 Gas-filled, three-cathode 1-bit binary counter or switching tube, 7-pin base
• 6900 Dual power triode for pulse applications in missiles, avionics and industrial systems; noval base
• 6922 (E88CC, industrial version of 6DJ8/ECC88)
• 6973 Power pentode similar in shape, size, and pinbase to the EL84/6BQ5, but with a high gain for more than double the output range. Popular in some makes of 1960s era guitar amplifiers, though rarely implemented in modern times.

7000s

• 7189/6BQ5/EL84 AF Power pentode
• 7189A similar to 6BQ5/EL84
• 7199 Split triode-pentode, noval pinbase. Similar to 6U8.
• 7289 3 GHz, 40 W UHF planar power triode
• 7308/E188CC Premium version of 6922
• 7360 Beam deflection tube, used as balanced modulator/mixer up to 100 MHz
• 7586 First Nuvistor available on the market, medium-mu triode
• 7587 Nuvistor Sharp cutoff tetrode
• 7591 Beam power pentode, octal pinbase. Found in many guitar amps made by Gibson and Ampeg.
• 7868 Beam power pentode, magnoval pinbase version of 7591. Found in many of the once popular Challenger series PA amps made by Bogen Communications, also found in some guitar amplifiers made by Ampeg.
• 7895 Improved 7586 Nuvistor with higher mu

8000s

• 8056 Nuvistor triode for low supply voltage
• 8058 Nuvistor triode with grid on envelope and an anode cap, for grounded-grid UHF circuits
• 8122 Forced-air cooled, 300 W@470 MHz beam power tetrode
• 8393 Nuvistor Medium-mu triode, used in Tektronix oscilloscopes, 12.6 Volt heater
• 8873 500 MHz, 200 W plate dissipation power triode
• 8874 500 MHz, 400 W plate dissipation power triode
• 8875 500 MHz, 300 W plate dissipation power triode
• 8877 = 3CX1500A7 Ceramic, forced air cooled, 1.5 kW power triode
• 8974 (X-2159) Giant water-cooled megawatt-class tetrode used for very high-power broadcast and industrial service; possibly the most powerful tube ever commercially produced

List of European Mullard-Philips tubes, with American equivalents

Most post-war European thermionic valve (vacuum tube) manufacturers have used the Mullard-Philips tube designation naming scheme.

Special quality variants may have the letters "SQ" appended, or the device description letters may be swapped with the numerals (e.g. an E82CC is a special quality version of an ECC82)

Note: Typecode explained above. The part behind a slash ("/") is the RMA/RETMA/EIA equivalent.

A - 4 V heater

AB

• AB1 Dual diode
• AB2 Dual diode

ABC

• ABC1 Dual diode - sharp-cutoff pentode, CBC1 with a different heater, 1930s European radios.

ABL

• ABL1 Dual diode - power pentode, 1930s European radios.

AC

• AC2 Triode for use as AF amplifier or as oscillator together with an AH1 mixer; 8-pin base, EC2 with a different heater
• AC50/4686 3 mA_avg, 300 mA_peak, Argon-filled triode thyratron, 8-pin base with grid on top cap, for relaxation oscillators up to 50 kHz
• AC100 Triode for use as AF amplifier or as oscillator together with an AH1 mixer; AC2 with a different base
• AC101 Triode for use as AF amplifier or as oscillator together with an AH1 mixer; AC2 with a different base
• AC701 Subminiature AF triode, 4-pin all-glass pigtailed with grid on top cap, for condenser microphone preamplifiers
• AC761 Subminiature AF triode, 4-pin all-glass pigtailed with grid on top wire, for microphone preamplifiers

ACH

• ACH1 Triode-Hexode mixer

A D

• AD1 4.2 W Power triode
• AD100 1.7 W Power triode, 5-pin base
• AD101 1.7 W Power triode, 7-pin base
• AD102 5.5 W Power triode

AF

• AF2 Remote-cutoff pentode
• AF3 Remote-cutoff pentode. Identical to CF3 except for heater ratings
• AF7 Sharp-cutoff pentode
• AF100 Wide band, sharp-cutoff pentode

AH

• AH1 Remote-cutoff Hexode for RF gain control or modulator, CH1 with a different heater
• AH100 Remote-cutoff Hexode for RF gain control or modulator

AK

• AK1 Pentagrid converter, 1930s European radios. UX7 base.
• AK2 Pentagrid converter, CK1 with a different heater, 1930s European radios. Ct8 base, similar to EK2.

AL

• AL1 AF Power pentode, 1930s European radios
• AL2 AF Power pentode, 1930s European radios. Ct8 base.
• AL3 AF Power pentode, 1930s European radios
• AL4 AF Power pentode, 1930s European radios
• AL5 Identical to EL5 except for heater ratings
• AL860 RF/AF Power pentode, noval base

AM

• AM1 "Magic Cross"-type tuning indicator, EM1 with a different heater
• AM2/4677 "Magic Eye"-type tuning indicator, identical to CM2 and EM2 except for heater ratings

AN

• AN1 300 mA_avg, 2 A_peak, 15 A_surge, Gas-filled triode thyratron with negative control characteristic. British 5-pin base, for industrial control applications

AX

• AX1/4652 125 mA, Full-wave mercury-vapor rectifier, 4-pin base
• AX50 275 mA, Full-wave mercury-vapor rectifier, 4-pin base

AZ

• AZ1 100 mA Full-wave power rectifier, Ct8 base, 8-pin side-contact
• AZ2 160 mA Full-wave power rectifier, Ct8 base, 8-pin side-contact
• AZ3 120 mA Full-wave power rectifier, Ct8 base, 8-pin side-contact
• AZ4 200 mA Full-wave power rectifier, Ct8 base, 8-pin side-contact
• AZ11 Full-wave power rectifier, AZ1 with G8A 8-pin German metal octal base
• AZ12 Full-wave power rectifier, AZ4 with G8A 8-pin German metal octal base
• AZ21 120 mA Full-wave power rectifier, Loctal base
• AZ31 Full-wave power rectifier, AZ1 with 5-pin Octal base
• AZ32 Full-wave power rectifier, AZ2 with 5-pin Octal base
• AZ33 120 mA Full-wave power rectifier, 4-pin Octal base
• AZ41 70 mA Full-wave power rectifier, Rimlok base
• AZ50 300 mA Full-wave power rectifier, Rimlok base

B - 180 mA heater

BB

• BB1 Shielded common-cathode dual diode, CB2 with a 16 V heater and a European 5-pin base with one anode on top cap

BCH

• BCH1 Triode-hexode mixer, ACH1 with a 24 V heater and a German Hexode base, hexode control grid on top cap

BL

• BL2 Power pentode, CL2 with a 30 V heater and a European 5-pin base with the control grid on top cap

C - 200 mA heater

CB

• CB1 Dual diode, P base, 8-pin side-contact, 1930s European radios.
• CB2 Dual diode, P base, 8-pin side-contact, 1930s European radios.

CBC

• CBC1 Dual diode and triode, ABC1 with a different heater, 1930s European radios.

CBL

• CBL1 Dual diode and power pentode, 1930s European radios.
• CBL6 Dual diode and power pentode, 1930s European radios.
• CBL31 Dual diode and power pentode, CBL1 with a different base, 1930s European radios.

CC

• CC2 Triode, AC2 with a different heater, 1930s European radios.

CCH

• CCH1 Triode-hexode mixer, 1930s European radios.
• CCH2 Triode-hexode mixer, 1930s European radios.
• CCH35 Triode-hexode mixer, ECH3 with a different heater and base, 1930s European radios.

CF

• CF1 Sharp-cutoff pentode, 1930s European radios.
• CF2 Remote-cutoff pentode, 1930s European radios.
• CF3 Remote-cutoff pentode, AF3 with a different heater, 1930s European radios.
• CF7 Sharp-cutoff pentode, AF7 with a different heater, 1930s European radios.
• CF50 Microphone preamplifier sharp-cutoff pentode
• CF51 Microphone preamplifier sharp-cutoff pentode

CH

• CH1 Heptode mixer, AH1 with a different heater, 1930s European radios.

CK

• CK1 Octode pentagrid converter, AK2 with a different heater, 1930s European radios.
• CK3 Octode pentagrid converter, EK3 with a different heater, 1930s European radios.

CL

• CL1 Power pentode, 1930s European radios.
• CL2 Power pentode, BL2 with a different heater, 1930s European radios.
• CL4 AF power pentode, 1930s European radios.
• CL6 Power pentode, 1930s European radios.
• CL33 AF power pentode, CL4 with an octal base, 1930s European radios.

CM

• CM2 "Magic Eye"-type tuning indicator; has a 6.3 V/200 mA heater and was therefore marketed as C/EM2; identical AM2 except for heater ratings

CY

• CY1 250 V, 80 mA Half wave rectifier, Ct8 base, 1930s European radios.
• CY2 Separate-cathode dual 250 V, 60 mA rectifier, Ct8 base, for use as half wave rectifier or as voltage doubler. 1930s European radios.
• CY31 CY1 with International Octal base, 1930s European radios.
• CY32 CY2 with International Octal base, 1930s European radios.

D - 1.4 V filament/heater

Note: D-type tubes except some rectifiers are directly heated.

DA

• DA50 Subminiature diode, 3-pin all-glass pigtailed
• DA90 Indirectly heated AM detector diode, miniature 7-pin base
• DA101 Diode, miniature 7-pin base

DAC

• DAC21 AM detector diode and AF triode
• DAC22 AM detector diode and AF triode
• DAC25 AM detector diode and AF triode
• DAC31 AM detector diode and AF triode
• DAC32 AM detector diode and AF triode
• DAC41w AM detector diode and AF triode

DAF

• DAF11 AM detector diode and AF pentode, wide-range heater
• DAF26 AM detector diode and AF pentode
• DAF40 AM detector diode and AF pentode
• DAF41 AM detector diode and AF pentode
• DAF70 Subminiature AM detector diode and AF pentode, all-glass pigtailed
• DAF91/1S5 AM detector diode and AF pentode, miniature 7-pin base
• DAF92 AM detector diode and AF pentode, miniature 7-pin base
• DAF96/1AH5 AM detector diode and AF pentode, miniature 7-pin base
• DAF191 AM detector diode and AF pentode, miniature 7-pin base
• DAF961 AM detector diode and AF pentode, miniature 7-pin base

DAH

• DAH50 Low voltage diode-heptode with space charge grid

DBC

• DBC21 Dual diode and Triode

DC

• DC11 AF driver triode for DDD11, wide-range heater
• DC25 AF driver triode for DDD25
• DC41w Driver triode
• DC70/6375 Subminiature UHF Triode for walkie-talkies, all-glass pigtailed
• DC80/1E3 Triode, oscillator/mixer/amplifier
• DC90 Triode, FM receiver oscillator/mixer/amplifier, miniature 7-pin base
• DC96 Triode, FM receiver oscillator/mixer/amplifier, miniature 7-pin base
• DC760 Subminiature Electrometer inverted triode for probes, all-glass pigtailed
• DC761 Subminiature UHF Triode, all-glass pigtailed
• DC762 Subminiature Electrometer inverted triode for probes, 100 fA grid current, all-glass pigtailed

—Special quality:

• D1C (957) Acorn UHF triode
• D2C (958) Acorn UHF triode

DCC

• DCC90 Dual triode, RF amplifier or oscillator, miniature 7-pin base

DCF

• DCF60/1V6 Triode and pentode, oscillator/mixer, all-glass 7-pin pigtailed

DCH

• DCH11 Remote-cutoff triode/hexode mixer, wide-range heater
• DCH21 Remote-cutoff triode/hexode mixer
• DCH25 Remote-cutoff triode/hexode mixer
• DCH41w Remote-cutoff triode/hexode mixer

DD

• DD960 VHF power triode, miniature 7-pin base

DDD

• DDD11 Dual AF power triode, wide-range heater - preferred driver is DC11
• DDD25 Dual AF power triode - preferred driver is DC25
• DDD41w Dual power triode

DF

• DF11 Remote-cutoff RF/IF pentode, wide-range heater
• DF21 Sharp-cutoff RF/IF/AF pentode
• DF22 Remote-cutoff RF/IF pentode
• DF25 Remote-cutoff RF/IF pentode
• DF26 Sharp-cutoff RF/IF pentode
• DF33 Remote-cutoff RF/IF pentode
• DF41w Remote-cutoff RF/IF pentode
• DF60/5678 Subminiature sharp-cutoff RF/IF/AF pentode, all-glass pigtailed
• DF61 Subminiature sharp-cutoff RF or mixer pentode, all-glass pigtailed
• DF62/1AD4 Subminiature sharp-cutoff RF pentode, all-glass pigtailed, for use as RF/IF stage
• DF63 Subminiature remote-cutoff RF pentode, all-glass pigtailed, for use as RF/IF stage
• DF64 Subminiature AF pentode, all-glass pigtailed, for use in hearing aids
• DF65 Subminiature AF pentode, all-glass pigtailed, for use in hearing aids
• DF66 Subminiature AF pentode, all-glass pigtailed, for use in hearing aids
• DF67/6008 Subminiature AF pentode, all-glass pigtailed, for use in hearing aids
• DF70 Subminiature AF pentode, all-glass pigtailed, for use in hearing aids
• DF72 Subminiature sharp-cutoff RF pentode, all-glass pigtailed, for use as RF/IF stage
• DF73 Subminiature remote-cutoff RF pentode, all-glass pigtailed, for use as RF/IF stage
• DF91/1T4 Remote-cutoff RF/IF pentode, miniature 7-pin base
• DF92/1L4 Sharp-cutoff RF/IF pentode, miniature 7-pin base
• DF96/1AJ4 Remote-cutoff RF/mixer pentode, miniature 7-pin base
• DF97/1AN5 Remote-cutoff RF/IF pentode, miniature 7-pin base
• DF161 Subminiature AF pentode, all-glass pigtailed, for use in hearing aids
• DF167 Subminiature AF pentode, all-glass pigtailed, for use in hearing aids
• DF191 RF pentode, miniature 7-pin base
• DF651 (CK549DX) Subminiature AF pentode, all-glass pigtailed, for use in hearing aids
• DF668 Subminiature RF pentode, all-glass pigtailed
• DF669 Subminiature RF/IF pentode, all-glass pigtailed
• DF703 (CK5886) Subminiature electrometer pentode, envelope has a moisture-repellent coating, all-glass pigtailed, for probe amplifiers
• DF904/1U4/5910 Sharp-cutoff SW/VHF pentode, miniature 7-pin base
• DF906 Sharp-cutoff SW/VHF pentode, miniature 7-pin base
• DF961 Sharp-cutoff SW/VHF pentode, miniature 7-pin base

—Special quality:

• D1F D11F with a hand grip
• D2F D12F with a hand grip
• D3F (959) Acorn VHF pentode
• D11F Acorn remote-cutoff RF/IF/AF pentode for portable transceivers
• D12F Acorn RF/IF/AF pentode for portable transceivers

DK

• DK21 Octode pentagrid converter
• DK32/1A7 Heptode pentagrid converter
• DK40 Octode pentagrid converter
• DK91/1R5 Heptode pentagrid converter, miniature 7-pin base
• DK92/1AC6 Heptode pentagrid converter, miniature 7-pin base
• DK96/1AB6 Heptode pentagrid converter, miniature 7-pin base
• DK192 Heptode pentagrid converter, miniature 7-pin base
• DK962 Heptode pentagrid converter, miniature 7-pin base

DL

• DL11 350 mW AF Power pentode, wide-range heater
• DL21 700 mW AF Power pentode
• DL25 Power pentode
• DL29/3D6 Power pentode
• DL33/3Q5GT 400 mW AF Power pentode
• DL35 400 mW Power pentode
• DL41 600 mW Power pentode

• DL41w Bowl Power pentode

• DL64 Subminiature AF power pentode, all-glass pigtailed, for use in hearing aids, U_A = 15 V, U_Amax = 45 V
• DL65 Subminiature AF power pentode, all-glass pigtailed, for use in hearing aids, DL67/6007 with a different pinout, U_A = 22.5 V, U_Amax = 45 V
• DL66 Subminiature AF power pentode, all-glass pigtailed, for use in hearing aids, U_A = 22.5 V, U_Amax = 45 V
• DL67/6007 Subminiature AF power pentode, all-glass pigtailed, for use in hearing aids, DL65 with a different pinout, U_A = 22.5 V, U_Amax = 45 V
• DL68 Subminiature AF power pentode, all-glass pigtailed, for use in hearing aids, U_A = 22.5 V, U_Amax = 45 V
• DL69 Subminiature power pentode, all-glass pigtailed, U_A = 90 V
• DL70 Subminiature VHF power pentode up to 200 MHz, all-glass pigtailed, for use in walkie-talkies, U_A = 150 V
• DL71 Subminiature AF power pentode, all-glass pigtailed, for use in hearing aids, U_A = 22.5 V, U_Amax = 45 V
• DL72 Subminiature AF power pentode, all-glass pigtailed, for use in hearing aids, U_Amax = 45 V
• DL73 (CV2299) Subminiature VHF power pentode up to 200 MHz, all-glass pigtailed, for use in walkie-talkies, U_A = 150 V
• DL91/1S4 Power pentode, miniature 7-pin base
• DL92/3S4 270 mW AF Power pentode, miniature 7-pin base
• DL93/3A4 1.2 W RF/AF Power pentode, miniature 7-pin base
• DL94/3V4 1.3 W AF Power pentode, miniature 7-pin base
• DL95/3Q4 270 mW AF Power pentode, miniature 7-pin base
• DL96/3C4 440 mW AF Power pentode, miniature 7-pin base
• DL98/3B4 1.25 W RF power pentode up to 100 MHz, miniature 7-pin base
• DL161 Subminiature AF power pentode, all-glass pigtailed, for use in hearing aids
• DL167 1.8 mW Subminiature AF power pentode, all-glass pigtailed, for use in hearing aids
• DL192 150 mW AF Power pentode, miniature 7-pin base
• DL193 650 mW AF Power pentode, miniature 7-pin base
• DL620 110 mW Subminiature power pentode, all-glass pigtailed, U_Amax = 90 V
• DL907 SW/VHF power pentode, miniature 7-pin base
• DL962 150 mW AF power pentode, miniature 7-pin base
• DL963 RF/AF power pentode, miniature 7-pin base

DLL

• DLL21 1.5 W AF Dual power pentode
• DLL101 Dual power pentode, miniature 7-pin base
• DLL102 Dual power pentode, miniature 7-pin base

DM

• DM21 "Magic Eye"-type tuning indicator
• DM70/1M3 Subminiature "Magic Band"-type tuning/level indicator, all-glass pigtailed
• DM71/1N3 Subminiature "Magic Band"-type tuning/level indicator, all-glass pigtailed
• DM160/6977 (ИВ-15) First vacuum fluorescent display, single segment, for use as flip-flop status indicator in transistorized computers. All-glass pigtailed

DY

• DY30 30 kV CRT EHT rectifier
• DY51 Half-indirectly-heated 15 kV portable-TV CRT EHT rectifier, filament internally connected to cathode, all-glass, filament pigtails on one end, anode pigtail on the other
• DY70 10 kV CRT EHT rectifier, 3-pin all-glass pigtailed, anode on top wire
• DY80 23 kV CRT EHT rectifier, noval base
• DY86/1S2 Half-indirectly-heated 18 kV CRT EHT rectifier, noval base, filament internally connected to cathode. Identical to EY86 except for heater ratings
• DY87/1S2A DY86/1S2 with chemically treated envelope to avoid flush-over in high-humidity and low atmospheric-pressure conditions. Identical to EY87 except for heater ratings
• DY802 Half-indirectly-heated 23 kV CRT EHT rectifier, noval base, filament internally connected to cathode. Identical to PY802 except for heater ratings
• DY900 Half-indirectly-heated 16 kV CRT EHT rectifier, miniature 7-pin base, filament internally connected to cathode

E - 6.3 V heater

EA

• EA40 7 kV, 25 mA Diode, 4-pin Rimlock base
• EA50/2B35 Diode for TV detectors, 3-pin all-glass pigtailed with anode top cap
• EA52/6923 Instrumentation rectifier diode up to 1 GHz, 3-pin all-glass pigtailed with anode top cap
• EA53 Co-axial instrumentation rectifier diode up to 1 GHz, all-glass with anode top cap
• EA76 Diode, 5-pin all-glass pigtailed
• EA111 Diode for time bases, 8-pin base
• EA766 Diode, 5-pin all-glass pigtailed
• EA960 100 V_PIV VHF Diode, miniature 7-pin base
• EA961 2 kV_PIV VHF Diode, miniature 7-pin base
• EA962 100 V_PIV VHF Diode with extremely small distance between cathode and anode for extended frequency range, miniature 7-pin base

EAA

• EAA11 Dual diode, 8-pin base
• EAA91/6AL5 Dual diode with separate cathodes, miniature 7-pin base, identical to HAA91/12AL5, UAA91 and XAA91/3AL5 except for heater ratings, EB91 with a shorter envelope
• EAA171 Dual diode, separate cathodes, gnome tube
• EAA901S/5726 Dual RF diode, miniature 7-pin base

—Special quality:

• E91AA Dual diode, miniature 7-pin base

EAB

• EAB1 Triple diode with common cathode

EABC

• EABC80/6AK8 High-mu triode, triple low-voltage diode (two on common cathode with triode, one with independent cathode). Miniature 9-pin noval base, used as an AF amplifier, AM detector and ratio detector in AC-powered post-war European AM/FM radios. Electronically identical to American types 6AK8 (usually marked 6AK8/EABC80), 6T8, and 6T8A; also DH719. Identical to 5T8, 6T8, HABC80/19T8, PABC80/9AK8 and UABC80/12AK8 except for heater ratings

EAC

• EAC91 Diode/triode UHF mixer

EAF

• EAF21 Diode - pentode, UAF21 with a different heater
• EAF41 Diode - remote-cutoff RF/IF/AF pentode, Rimlock base, UAF41 with a different heater
• EAF42/6CT7 Diode - remote-cutoff RF/IF/AF pentode, Rimlock base
• EAF801 Diode - remote-cutoff pentode, Noval base

EAM

• EAM86/6GX8 Diode - "Magic Band"-type tuning/level indicator

EB

• EB1 Low-power dual diode
• EB4 Low-power dual diode, identical to EB11 or EB34 except for basing
• EB11 Low-power dual diode, identical to EB4 or EB34 except for basing
• EB34 Low-power dual diode, identical to EB4 or EB11 except for basing
• EB40 Low-power dual diode
• EB41 Low-power dual diode
• EB91 Dual diode with separate cathodes, miniature 7-pin base, for FM ratio detectors, EAA91/6AL5 with a longer envelope

EBC

• EBC1 Low-power dual diode and triode, ABC1 with a different heater
• EBC3 Low-power dual diode and triode
• EBC11 Low-power dual diode and triode
• EBC33 Low-power dual diode and triode, EBC3 with a different base
• EBC41 Low-power dual diode and triode, EBC81/6BD7A with a different basing
• EBC81/6BD7A Low-power dual diode and triode, EBC41 with a different basing
• EBC90/6AT6 High-mu triode and common cathode dual diode, miniature 7-pin base, HBC90/12AT6 with a different heater
• EBC91/6AV6 High-mu AF triode and common cathode dual diode, for use in FM ratio detectors, miniature 7-pin base, HBC91/12AV6 with a different heater

EBF

• EBF2 Common-cathode dual diode and remote-cutoff RF/IF/AF pentode, P base, identical to EBF11 and EBF35 except for basing
• EBF11 Common-cathode dual diode and RF/IF/AF pentode, Y base, identical to EBF2 and EBF35 except for basing, and to VBF11 except for heater ratings
• EBF15 Dual diode and pentode, UBF15 with a different heater
• EBF32 Common-cathode dual diode and remote-cutoff RF/IF pentode, 8-pin base with g1 on cap
• EBF35 Common-cathode dual diode and remote-cutoff RF/IF pentode, 8-pin base with g1 on cap, identical to EBF2 and EBF11 except for basing
• EBF80/6N8 (WD709) Common-cathode dual diode and remote-cutoff pentode, noval base
• EBF83/6DR8 Common-cathode dual diode and pentode, anode voltage 6 to 50 V, for use as IF amplifier, detector and AGC diode in vehicle equipment, noval base
• EBF89/6DC8/7125 Common-cathode dual diode and RF/IF pentode, noval base
• EBF171 Dual Diode and remote-cutoff RF/IF/AF pentode; the first gnome tube, a modified and repackaged EBF11

EBL

• EBL1 Dual diode and power pentode, identical to EBL21 and EBL31 except for basing and heater ratings
• EBL21 (WD709), Dual diode and power pentode, identical to EBL1 and EBL31 except for basing and heater ratings
• EBL31 Dual diode and power pentode, identical to EBL1 and EBL21 except for basing and heater ratings
• EBL71 Dual diode and power pentode

EC

• EC2 Triode for use as AF amplifier or as oscillator, 8-pin base, AC2 with a different heater
• EC40 VHF Triode up to 500 MHz, EC80 with a different basing
• EC41 UHF oscillator triode, EC81 with a different basing
• EC50 Helium-filled triode thyratron for use as a horizontal sweep, sawtooth waveform generator in oscilloscopes
• EC52 RF triode for use as an oscillator
• EC53 VHF triode for use as an oscillator up to 600 MHz
• EC55/5861 (R243) 3 GHz, 10 W Disc-seal UHF triode
• EC56 4 GHz Disc-seal microwave triode
• EC57 (EC157) Disc-seal microwave triode
• EC70/6778 Subminiature UHF triode for use as an oscillator in the 500 MHz range, 8-pin all-glass pigtailed
• EC71/5718 Subminiature UHF triode up tp 1 GHz, for use as an oscillator in the 500 MHz range, 8-pin all-glass pigtailed
• EC80/6Q4 VHF Triode up to 500 MHz
• EC81/6R4 UHF oscillator triode
• EC84/6AJ4 High-mu triode
• EC86/6CM4 UHF triode, PC86/4CM4 with a different heater
• EC88/6DL4 UHF triode, PC88/4DL4 with a different heater. This and the EC86 were often encountered in UHF TV tuners, the latter as a self oscillating mixer
• EC90 Power triode up to 150 MHz, single ECC82/12AU7 system
• EC91/6AQ4 VHF triode up to 250 MHz
• EC92/6AB4 VHF triode for FM receicer frontends, single ECC81/12AT7 system, UC92/9AB4 with a different heater
• EC94/6AF4 UHF mixer/oscillator triode
• EC95 VHF triode with variable mutual conductance, PC95 with a different heater
• EC97/6FY5 Frame-grid VHF triode, identical to PC97/4FY5 and XC97 except for heater ratings
• EC98 UHF triode
• EC157/8108 4 GHz, 12.5 W Disc-seal microwave triode
• EC158 Low-voltage, 4 GHz, 30 W disc-seal microwave triode
• EC760 (5718) Subminiature VHF mixer/oscillator triode up to 500 MHz, 7-pin all-glass pigtailed
• EC860 20 mA_avg, 500 mA_pk Helium-filled grid-turn-off triode thyratron e.g. for relaxation oscillators up to 150 kHz, noval base
• EC900 VHF triode, PC900 with a different heater

—Special quality:

• EC1000 Triode for use as amplifier in probes
• EC1030 Indirectly heated UHF triode, hot-standby (no cathode current) resistant, all-glass pigtailed with 8 tinned, 38 mm long wires
• EC1031 EC1030 with 5.5 mm long, gold-plated pins for insertion into a special socket
• EC8010 UHF triode for use as amplifier or oscillator up to 1 GHz
• EC8020 UHF triode
• E1C/4671 (955) Acorn UHF triode
• E20C RF triode for wide band cascode circuits, Loctal B8G base
• E86C (EC806S) UHF triode up to 800 MHz, gold-plated pins
• E88C/8255 UHF triode for grounded-grid amplifiers, up to 1 GHz

ECC

• ECC32/6SN7 Separate cathodes dual AF triode, octal base
• ECC33 Separate cathodes, high-mu dual triode for use as a flip-flop, octal base
• ECC34 Separate cathodes, dual triode for use as a CRT vertical-deflection power multivibrator, octal base
• ECC35/6SL7 Separate cathodes, high-mu AF dual triode, octal base
• ECC40 Separate cathodes, AF dual triode, 8-pin Rimlock base
• ECC70/6021 Separate cathodes, subminiature VHF medium-mu dual triode, 8-pin all-glass pigtailed

ECC83/12AX7

• ECC81/12AT7 (6060, M8162, B309) High-mu dual triode, for use as RF amplifier/mixer in VHF circuits, noval base
• ECC82/12AU7 (6067, M8136, B329) Medium-mu dual triode for use as AF amplifier in TV receivers, noval base, identical to PCC82 or XCC82 except for heater ratings
• ECC83/12AX7 (6057, M8137, B339) High-mu dual triode for use as a high-gain AF amplifier, noval base
• ECC84/6CW7 Dual VHF triode for cascode amplifiers, noval base. Identical to PCC84/7AN7 and UCC84 except for heater ratings
• ECC85/6AQ8 Dual triode for use as VHF oscillator/mixer up to 200 MHz, noval base, identical to HCC85/17EW8, PCC85/9AQ8 and UCC85 except for heater ratings
• ECC86/6GM8 Dual low (12-25 V) anode voltage triode, noval base, for use in VHF tuners in vehicle equipment
• ECC87/6085 Renamed to E80CC/6085
• ECC88/6DJ8 Dual triode used as cascode RF amplifier in TV tuners and VHF receiver front ends, or as general-purpose instrumentation dual triode, noval base, PCC88/7DJ8 with a different heater
• ECC89/6ES8 Dual Triode used as cascode RF amplifier in TV tuners and VHF receiver front ends, or as general-purpose instrumentation dual triode, noval base

Notes:

• All ECC8x have separate cathodes.
• ECC81, 82 & 83 have the individual triode heaters internally series-connected, with the midpoint on a separate pin, so they could be run on both 6.3 V and 12.6 V (hence RETMA lists them as 12V types), which was useful in dual-system (6V and 12V) car radios.
• All other ECC8x have their heaters internally paralleled.

• ECC90 Common cathode dual triode for use as a flip-flop in computers, miniature 7-pin base
• ECC91/6J6 Common cathode dual VHF triode, miniature 7-pin base
• ECC92 Common cathode dual triode for use as a flip-flop in computers, miniature 7-pin base
• ECC99 Separate cathodes dual RF triode, noval base
• ECC171 Separate cathodes and separate heaters dual triode, 11-pin gnome tube with internal shield
• ECC180/6BQ7A Separate cathodes, dual VHF triode for cascode amplifiers
• ECC186/7316 Separate cathodes, dual triode for use in digital computers, withstands zero cathode current current for extended periods of time
• ECC189/6ES8 Separate cathodes, dual variable-mu VHF triode for cascode amplifiers; identical to PCC189/7ES8, XCC189/4ES8 and YCC189/5ES8 except for heater ratings
• ECC230/6AS7G/6080 Separate cathodes, dual low-mu power triode for use as series regulator in DC power supplies, servo applications, or as a horizontal booster triode in TV monitors, 8-pin base
• ECC801S/6201 Separate cathodes, dual RF triode
• ECC802S/6189 Separate cathodes, dual AF triode
• ECC803S/6057 Separate cathodes, dual low-microphonics AF triode
• ECC807S Separate cathodes, dual AF triode for high-gain preamplifiers
• ECC808/6KX8 Separate cathodes, dual AF triode for use as record head output tube in tape recorders
• ECC812 Separate cathodes, dual shielded triode for color TV chrominance outputs in SECAM TV receivers
• ECC832/12DW7/7247 Dual AF triode, a combination of one ECC83/12AX7 system for use as a high-gain amplifier and one ECC82/12AU7 system for use as a phase inverter or cathode follower
• ECC960 Common cathode, dual triode for use as a flip-flop in computers

—Special quality:

• ECC2000 VHF separate cathodes, dual triode with neutralization screen, for use in cascode amplifiers up to 300 MHz, 10-pin base
• ECC8100 VHF separate cathodes, dual triode with neutralization screen ("Neutrode") connected to the heater, for use in cascode amplifiers, noval base
• E80CC/6085 Separate cathodes, dual triode for use as DC or AF amplifier
• E81CC/6201 Separate cathodes, dual triode for AF and RF amplifiers, mixers up to 300 MHz, oscillators, impulse circuits; withstands zero cathode current current for extended periods of time
• E82CC/6189 Separate cathodes, dual triode for use as amplifier or multivibrator
• E83CC/6681 Separate cathodes, low-microphonics dual triode
• E88CC/6922 Separate cathodes, dual triode, gold-plated pins
• E90CC/5920 Common cathode, dual triode for use as a flip-flop in computers
• E92CC Common cathode, dual triode for use as a flip-flop in computers
• E180CC/7062 Separate cathodes, dual triode for use as a flip-flop in computers
• E181CC Separate cathodes, dual triode for use in digital computers, withstands zero cathode current current for extended periods of time
• E182CC/7119 Separate cathodes, dual triode for use as a flip-flop in computers
• E188CC/7308 Separate cathodes, dual triode for use as RF/IF/AF amplifier
• E283CC Separate cathodes, dual triode for use as AF or instrumentation amplifier
• E288CC/8223 Separate cathodes, dual triode for use in IF, RF and cascode amplifiers

ECF

• ECF1 Triode - Pentode
• ECF12 Triode - Pentode
• ECF80/6BL8 VHF mixer/oscillator triode/pentode, identical to LCF80/6LN8, PCF80/9A8, UCF80 and XCF80/4BL8 except for heater ratings
• ECF82/6U8 Triode - Pentode. Identical to PCF82/9U8A and XCF82 except for heater ratings
• ECF83 Triode - remote-cutoff pentode, low microphonics, for vehicle equipment
• ECF86/6HG8 VHF mixer/oscillator triode/pentode, identical to LCF86/5HG8, PCF86/7HG8, 8HG8 and XCF86/4HG8 except for heater ratings
• ECF174 Triode and pentode, gnome tube
• ECF200/6X9 Triode and pentode for use as IF amplifier in TV receivers, decal base, PCF200 with a different heater
• ECF201/6U9 Triode and pentode for use as IF amplifier and sync sep in TV receivers, decal base, identical to LCF201/5U9 and PCF201 except for heater ratings
• ECF202 Triode and pentode for use as SECAM chroma signal demodulators in analog color TV receivers, decal base
• ECF801/6GJ7 Triode and pentode for use as VHF mixer in TV receivers, noval base, identical to LCF801/5GJ7, PCF801/8GJ7 and XCF801/4GJ7 except for heater ratings
• ECF802/6JW8 Triode and pentode for use as reactance and sinewave oscillator in TV receivers, noval base, identical to LCF802/6LX8, PCF802/9JW8 and 5JW8 except for heater ratings
• ECF804 Triode and pentode for use as wide band amplifier, noval base, PCF804 with a different heater
• ECF805 Triode and pentode, noval base, PCF805/7GV7 with a different heater
• ECF812/6FL2 Triode and beam tetrode, noval base, PCF812/30FL2 with a different heater

—Special quality:

• ECF8070 Triode - Pentode
• E80CF/7643 Triode - pentode

ECH

• ECH3 Ct8-based Triode/hexode oscillator/mixer, ECH33 with a different basing
• ECH4 Ct8-based Triode/hexode oscillator/mixer, ECH21 with a different basing
• ECH11 (X143) Triode/hexode oscillator/mixer, VCH11 with a different heater
• ECH21 (X143) Triode/hexode oscillator/mixer, ECH4 with a different basing
• ECH33 Triode/hexode oscillator/mixer, ECH3 with a different basing
• ECH35 (X147) Triode/hexode oscillator/mixer
• ECH41 Triode/hexode oscillator/mixer
• ECH42/6CU7 Triode/hexode oscillator/mixer, UCH42 with a different heater
• ECH43 Triode/hexode oscillator/mixer, low-microphonics version of ECH42; UCH43 with a different heater
• ECH71 Triode/hexode oscillator/mixer
• ECH80/6AN7 Triode-hexode oscillator/mixer
• ECH81/6AJ8 (X719) Triode/hexode oscillator/mixer, XCH81 with a different heater
• ECH83/6DS8 Low (12-25 V) anode voltage, Triode/hexode oscillator/mixer, for use in vehicle equipment
• ECH84 Triode/hexode oscillator/mixer
• ECH171 Triode/remote-cutoff heptode Mixer, gnome tube
• ECH200 Triode/hexode, for TV sync sep, PCH200 with a different heater

—Special quality:

• ECH8000 Triode/hexode oscillator/mixer

ECL

• ECL11 Triode - power pentode
• ECL80/6AB8 Triode - power pentode
• ECL81 Triode - power pentode. Identical to PCL81 except for heater ratings
• ECL82/6BM8 AF triode - AF power pentode, identical to PCL82/16A8, UCL82/50BM8 and XCL82 except for heater ratings
• ECL83 Triode - power pentode, PCL83 with a different heater
• ECL84/6DX8 TV sync sep triode - CRT cathode drive power pentode, identical to LCL84/10DX8, PCL84/15DQ8 and XCL84/8DX8 except for heater ratings
• ECL85/6GV8 Triode - power pentode used in TV receivers for vertical timebase, generally as a multivibrator, with the pentode section doubling as one half of the multivibrator and the power output device, identical to LCL85/10GV8, PCL85/18GV8 and XCL85/9GV8 except for heater ratings
• ECL86/6GW8 AF Triode - AF power pentode, used for audio amplification in European TV receivers, PCL86/14GW8 with a different heater
• ECL113 Triode - AF power pentode, Rimlock Pico-8 base
• ECL200 Triode - CRT drive power pentode, decal base, PCL200 with a different heater
• ECL802 Triode - Power pentode for use as vertcal oscillator and output tube in TV receivers
• ECL805 Triode - Power pentode with separate cathodes, PCL805 with a different heater

ECLL

• ECLL800 Triode and dual screened power pentode, for 9.2 W (Class-B) or 8.5 W (Class-AB) AF push–pull power amplifiers. The triode shares its control grid with the 1st pentode and acts as a phase inverter for the 2nd pentode; both pentodes share screen and suppressor grids; noval base

ED

• ED111 6 W VHF power triode up to 85 MHz
• ED500 Identical to PD500 except for heater ratings
• ED501 27 kV Color CRT EHT shunt stabilizer triode

—Special quality:

• ED8000 Power triode for use in series-pass voltage regulators

EDD

• EDD11 Dual power triode
• EDD171 Dual high-mu power triode, gnome tube

EE

• EE1/4696 (EEP1) Single-ended secondary emission amplifier for use as a wide band amplifier and phase inverter
• EE50 Single-ended secondary emission amplifier for use in TV receivers

EEL

• EEL71 AF Tetrode - AF power pentode, 8-pin base, for use as audion detector, AF preamplifier, AF power amplifier
• EEL171 Remote-cutoff tetrode and 4-Watt power pentode, gnome tube

EEP

• EEP1 See EE1/4696

EF

• EF5 Remote-cutoff pentode
• EF6 RF Pentode, EF36 with a different basing
• EF8 Selektode, a remote-cutoff pentode with a beam-forming extra grid between comtrol and screen grids, intended to reduce screen current and hence anode/screen grid distribution noise (technically a hexode), EF38 with an 8-pin, side-contact base
• EF9 Pentode, identical to EF22, EF39/6K7 and EF41/6CJ5 except for basing
• EF11 Remote-cutoff pentode, EF111 with a different basing
• EF12 Pentode, EF112 with a different basing
• EF13 Remote-cutoff pentode
• EF14 Sharp-cutoff pentode, 8-pin base, identical to UF14 and VF14 except for heater ratings
• EF15 Remote-cutoff pentode, UF15 with a different heater
• EF22 Pentode, identical to EF9, EF39/6K7 and EF41/6CJ5 except for basing
• EF27 Pentode
• EF36 Pentode, EF6 with a different basing
• EF37/6J7 Sharp-cutoff pentode for use as a tuned RF amplifier, a (second) detector, or an AF amplifier; octal base with control grid on top-cap
• EF38 EF8 with an Octal base
• EF39/6K7 Remote-cutoff RF pentode for use as an IF amplifier or as a superheterodyne mixer (1st detector). Also used in test equipment. Octal base with control grid on top-cap, identical to EF4, EF22 and EF41/6CJ5 except for basing
• EF40 Pentode
• EF41/6CJ5 (62VP) Remote-cutoff pentode, identical to EF4, EF22 and EF39/6K7 except for basing
• EF42 Pentode, EF52 with a different basing
• EF43 Remote-cutoff pentode
• EF50 (EF53) Remote-cutoff pentode for use in the IF stages of 1940s TV and radar receivers
• EF51 Remote-cutoff pentode
• EF52 Pentode, EF42 with a different basing
• EF54 Pentode
• EF55 Pentode
• EF70 Subminiature pentode, suppressor grid available on separate pigtail and internally connected to a separate diode to prevent positive grid voltage, for use as a NAND gate in coincidence circuits; all-glass 8-pin pigtailed
• EF71/5899 (EF731) Subminiature remote-cutoff pentode, all-glass 8-pin pigtailed
• EF72 Subminiature sharp-cutoff RF pentode, all-glass 8-pin pigtailed
• EF73 Subminiature AF pentode, all-glass 8-pin pigtailed
• EF74 Subminiature, low-microphonics pentode, all-glass 8-pin pigtailed
• EF80/6BX6 (Z152) RF/IF/Video pentode, Noval base
• EF83 Remote-cutoff AF pentode, Noval base
• EF85/6BY7 (W719) Remote-cutoff wideband RF pentode, noval base, identical to HF85 and XF85 except for heater ratings

• EF86/6BK8 (6267, Z729) AF Pentode. Identical to PF86 and UF86 except for heater ratings, Noval base
• EF89/6DA6 Remote-cutoff RF pentode, Noval base
• EF91/6AM6 (6064, Z77, M8083, 8D3) Sharp-cutoff pentode, Miniature 7-pin base
• EF92/6CQ6 (M8161) Remote-cutoff RF pentode, Miniature 7-pin base
• EF93/6BA6 (W727) Remote-cutoff RF pentode, miniature 7-pin base, HF93/12BA6 with a different heater
• EF94/6AU6 Sharp-cutoff RF/IF/AF pentode, miniature 7-pin base, identical to HF94/12AU6 and XF94/3AU6 except for heater ratings
• EF95/6AK5 (5654, 408A, 62H1P, CV4010) RF Pentode, Miniature 7-pin base
• EF96/6AG5 Pentode, Miniature 7-pin base
• EF97/6ES6 Low (12-25 V) anode voltage, remote-cutoff RF/IF pentode, for use in vehicle equipment, Miniature 7-pin base
• EF98/6ET6 Low (12-25 V) anode voltage, sharp-cutoff pentode, for use as oscillator or IF/AF amplifier in vehicle equipment, Miniature 7-pin base
• EF111 Remote-cutoff pentode, EF11 with a different basing
• EF112 Pentode, EF12 with a different basing
• EF172 RF/IF/AF Pentode, gnome tube
• EF174 Pentode, gnome tube
• EF175 Remote-cutoff RF/IF pentode, gnome tube
• EF176 VHF Pentode, gnome tube
• EF177 VHF Pentode, gnome tube
• EF183/6EH7 Frame grid, remote-cutoff IF pentode for use in TV receivers, identical to LF183/YF183/4EH7 and XF183/3EH7 except for heater ratings
• EF184/6EJ7 Frame-grid, sharp-cutoff IF pentode for use in TV receivers, identical to LF184/YF184/4EJ7 and XF184/3EJ7 except for heater ratings
• EF410 RF/IF Pentode, Rimlock B8A base
• EF730/5636 Subminiature remote-cutoff RF/IF pentode, 8-pin all-glass pigtailed
• EF731 Subminiature remote-cutoff RF pentode, 8-pin all-glass pigtailed
• EF732 Subminiature sharp-cutoff RF pentode, 8-pin all-glass pigtailed
• EF734 Subminiature sharp-cutoff RF pentode, 8-pin all-glass pigtailed
• EF762 Subminiature sharp-cutoff RF/IF pentode, 8-pin all-glass pigtailed
• EF800 Long-life sharp-cutoff RF/IF pentode
• EF802 Long-life RF/IF pentode
• EF804 AF low-hum, low-microphonics pentode
• EF804S Ruggedized, long-life version of EF804
• EF805S Long-life remote-cutoff RF/IF pentode
• EF806S Ruggedized, long-life AF pentode
• EF816 Dual-anode pentode for TV receiver sync separation service
• EF860 Long-life sharp-cutoff RF pentode for use as preamplifier in telecomms wide-area receivers. Identical to IF860 except for heater ratings (300mA)

—Special quality:

• EF5000 secondary emission wide band pentode, noval base
• EF8010 Remote-cutoff RF/IF pentode
• E1F/4672 (954) Acorn UHF pentode
• E2F/4695 (956) Acorn UHF pentode
• E3F E13F with a hand grip
• E13F Acorn remote-cutoff RF/IF/AF signal/power pentode for portable transceivers
• E80F/6084 Electrometer pentode, gold-plated pins
• E83F/6689 Long-life, wide band pentode for use in telephone equipment, gold-plated pins
• E90F/6BH6/7693 RF Pentode
• E95F/6AK5W/5654 Pentode
• E99F/6BJ6/7694 Remote-cutoff RF pentode
• E180F/6688 Wide band pentode, wideband amplifier for professional equipment
• E186F/7737 Wide band pentode, wideband amplifier
• E280F/7722 Wide band pentode, wideband amplifier
• E282F Pentode, wideband amplifier up to 250 MHz
• E810F/7788 Wide band pentode, gold-plated pins

EFF

• EFF51 Dual VHF pentode up to 500 MHz

EFL

• EFL200/6Y9 Sync sep pentode and CRT cathode drive power pentode, decal base; identical to LFL200/11Y9 and PFL200/16Y9 except for heater ratings

EFM

• EFM1 Variable-mu AF pentode - "Magic Eye"-type tuning indicator
• EFM11 Variable-mu AF pentode - Tuning indicator

EFP

• EFP60 Secondary emission pentode for TV amplifiers

EH

• EH2 Remote-cutoff heptode pentagrid converter, separate oscillator
• EH81 (E81H) Heptode
• EH90/6CS6 Dual-control heptode for use in TV receivers
• EH171 Sharp-cutoff heptode, gnome tube
• EH860 Heptode
• EH900S/5915 Dual-control switching heptode

—Special quality:

• E91H/6687 Dual-control heptode for use as a NAND gate in a coincidence circuit

EK

• EK2 Octode pentagrid converter, similar to AK2, EK32 with a Ct8 base
• EK3 Octode pentagrid converter, CK3 with a different heater, similar to AK2, Ct8 base
• EK32 Octode pentagrid converter, EK2 with octal base and top cap
• EK90/6BE6 Heptode pentagrid converter

EL

• EL2 Power pentode, Ct8 base, grid on top cap, identical to EL32 except for basing
• EL3 Power pentode, Ct8 base, identical to EL11 and EL33 except for basing
• EL3G/6V6 Power pentode, "G" denotes an EL3 with an Octal base
• EL5 Power pentode, identical to AL5 except for heater ratings and to EL35 except for basing
• EL6 Power pentode, identical to EL12 except for basing
• EL8 Power pentode, identical to EL13 except for basing
• EL11 Power pentode, identical to EL3 and EL33 except for basing
• EL12 Power pentode, identical to EL6 except for basing
• EL13 Power pentode, identical to EL8 except for basing
• EL32 Power pentode, identical to EL2 except for basing
• EL33/6M6G Power pentode, parallel filament circuits, identical to EL3 and EL11 except for basing
• EL34/6CA7 Power pentode
• EL35 Power pentode, identical to EL5 except for basing
• EL36/6CM5 Audio or CRT horizontal deflection output power pentode, identical to EL12 except for basing and to and XL36/13CM5 except for heater ratings
• EL37/6L6 Power pentode
• EL38/6CN6 Power pentode, PL38 with a different heater
• EL41/6CK5 (N150) Power pentode, EL80 with a different basing
• EL42 (N151) Power pentode, EL85 with a different basing
• EL44 Power pentode, identical to UL44 except for heater ratings
• EL50/4654 80 W Power pentode
• EL51 140 W Power pentode
• EL60 Power pentode, EL34 with a different basing
• EL71/5902 Subminiature 4 W AF power pentode, 8-pin all-glass pigtailed
• EL80/6M5 Power pentode, EL41 with a different basing
• EL81/6CJ6 CRT horizontal deflection or AF power pentode
• EL82/6DY5 CRT vertical deflection or AF power pentode
• EL83/6CK6 CRT cathode drive power pentode
• EL84/6BQ5 (N709) AF Power pentode
• EL85/6BN5 6 W RF/AF power pentode up to 120 MHz, for use in mobile equipment, EL42 with a different basing
• EL86/6CW5 Audio or CRT vertical deflection output power pentode, identical to LL86/10CW5, PL84/15CW5 and XL86/8CW5 except for heater ratings
• EL90/6AQ5 (N727) 4.5 W AF Power pentode
• EL91/6AM5 (M8082, 709) 4 W AF Power pentode
• EL95/6DL5 Power pentode
• EL112 Radiation-cooled power transmitter pentode for 85W SW/VHF service, or for AF amplifiers. Identical to EL152 and EL401 except for basing
• EL136 Horizontal-output power pentode for 110° deflection color TV
• EL151 Power pentode
• EL152 Radiation-cooled power transmitter pentode for 85W SW/VHF service, or for AF amplifiers. Identical to EL112 and EL401 except for basing and to FL152 except for heater ratings
• EL153 RF power pentode
• EL156 Power pentode
• EL171 4-Watts Power pentode, gnome tube
• EL172 8-Watts Power pentode, gnome tube
• EL173 Power pentode, gnome tube, for TV receivers
• EL180/12BY7 Power pentode
• EL183 CRT cathode drive power pentode
• EL300/6FN5 CRT horizontal deflection output power pentode
• EL360 Power pentode for use in radar scanners, series regulators and pulse modulators
• EL401 Radiation-cooled power transmitter pentode for 85W SW/VHF service, or for AF amplifiers. Identical to EL112 and EL152 except for basing
• EL500/6GB5 CRT horizontal deflection output beam power pentode, magnoval base, identical to LL500/18GB5, PL500/27GB5 and XL500/13GB5 except for heater ratings
• EL502 CRT horizontal deflection output power pentode
• EL503 AF power pentode, magnoval base
• EL504 CRT horizontal deflection output power pentode, PL504 with a different heater
• EL508 CRT vertical deflection output power pentode, PL508/17KW6 with a different heater
• EL509/6KG6A CRT horizontal deflection output power pentode, PL509/40KG6A with a different heater
• EL511 Power pentode
• EL519 Power pentode, PL519 with a different heater
• EL802 CRT cathode drive power pentode, PL802 with a different heater
• EL803 Wide band power pentode
• EL804 Wide band power pentode
• EL805 CRT vertical deflection output power pentode, PL805 with a different heater
• EL806 CRT cathode drive power pentode
• EL821/6CH6 (6132) CRT cathode drive power pentode for use in high definition television equipment
• EL822 CRT cathode drive power pentode
• EL861 Long-life sharp-cutoff RF power pentode for use as output amplifier in telecomms wide-area transmitters, identical to IL861 except for heater ratings

—Special quality:

• EL3010 Power pentode
• EL5000 AF power pentode
• EL5070/8608 Wideband video power pentode, magnoval base
• EL8000 Power pentode
• E55L/8233 Wide-band power pentode for use as CRT vertical deflection electrode driver in oscilloscopes
• E80L/6227 AF Power pentode, gold-plated pins
• E81L/6686 Long-life power pentode for use in telephone equipment, gold-plated pins
• E84L/7320 Power pentode for use in AF amplifiers and stabilized power supplies
• E130L/7534 Wide band power pentode
• E235L/7751 Power pentode
• E236L Power pentode

ELL

• ELL1 Dual power pentode
• ELL80/6HU8 Dual power pentode, miniature 9-pin base

EM

• EM1 (4678) "Magic Eye"-type tuning indicator, Ct8 Base
• EM2 "Magic Eye"-type tuning indicator; has a 6.3 V/200 mA heater and was therefore marketed as C/EM2; identical AM2 except for heater ratings
• EM4 Dual-sensitivity, "Magic Eye"-type tuning indicator, EM34 with a Ct8 Base
• EM5 Dual-sensitivity, "Magic Eye"-type tuning indicator, EM11 or EM35 with a Ct8 Base
• EM11 Dual-sensitivity, "Magic Eye"-type tuning indicator, EM5 or EM35 with an 8-pin base
• EM34/6CD7 Dual-sensitivity, "Magic Eye"-type tuning indicator, EM4 with a different base
• EM35 Dual-sensitivity, "Magic Eye"-type tuning indicator, EM5 or EM11 with a different base
• EM71 "Magic Fan"-type tuning indicator, octal B8D/F base, HM71 with a different heater
• EM72 EM71 with two segments of the fluorescent screen uncoated with phosphor
• EM80/6BR5 "Magic Fan"-type tuning indicator for AM receivers, noval B9A base
• EM81/6DA5 "Magic Fan"-type tuning indicator, EM80/6BR5 with intensity control, noval B9A base
• EM83 "Magic Balance"-type dual tuning/level indicator, two DC amplifier triodes and one electron gun for two separate screen anodes, noval B9A base
• EM84/6DH7/6FG6 "Magic Band"-type tuning/level indicator, noval B9A base
• EM85 "Magic Fan"-type tuning indicator, EM71 with noval B9A base, identical to HM85 and UM85 except for heater ratings
• EM87/6HU6 (CV10407) "Magic Band"-type tuning/level indicator, noval B9A base
• EM171 Dual-sensitivity tuning indicator, gnome tube
• EM800 "Magic Band"-type tuning/level indicator, noval B9A base
• EM840 "Magic Band"-type tuning/level indicator, noval B9A base

—Special quality:

• E82M "Magic Rectangle"-type dual tuning/level indicator, two DC amplifier triodes control separate deflection rods before a 17mmx20mm screen anode, noval B9A base

EMM

• EMM801 Dual, "Magic Band"-type indicator for voltage comparison
• EMM803 Dual, "Magic Band"-type tuning indicator for FM-stereo receivers (field strength, 19kHz pilot present), noval B9A base

EN

• EN31 10 mA_avg, 750 mA_peak, Helium-filled, indirectly heated triode thyratron for high-frequency timebases and control equipment, international octal base with anode cap
• EN32/6574 300 mA_avg, 2 A_peak, 10 A_surge, Gas-filled, indirectly heated tetrode thyratron with negative control characteristic; for industrial control applications, international octal base
• EN70 20 mA_avg, 100 mA_peak, Subminiature, gas-filled, indirectly heated tetrode thyratron with negative control characteristic, 8-pin all-glass pigtailed
• EN91/2D21 (PL21, PL2D21, CV797) 100 mA_avg, 500 mA_peak, 10 A_surge, Gas-filled, indirectly heated tetrode thyratron, negative starter voltage, miniature 7-pin base, for relay and grid-controlled rectifier service
• EN92 25 mA_avg, 100 mA_peak, 2 A_surge, Gas-filled, indirectly heated tetrode thyratron, negative starter voltage, miniature 7-pin base, for industrial control

EQ

• EQ40 Nonode for FM quadrature detection
• EQ80/6BE7 Nonode for FM quadrature detection or as phase detector in TV flywheel sync circuits
• EQ171 Nonode, gnome tube

ES

• ES111 TV sync oscillator (German: Kipp-Pentode), a special power relaxation oscillator pentode, an attempt to cut costs on TV receiver production; one ES111 each were needed for vertical and horizontal deflection; the output power for the deflection yoke was extracted not from the anode, but from the screen grid, the sync pulses were applied to the suppressor grid via a separate pin. The anode acted only as a small-signal amplified/gated-sync output which was added to the feedback from an auxiliary winding on the deflection yoke, and fed to the control grid. As there was no vertical deflection output transformer, a secondary, magnetically decoupled vertical deflection yoke received a variable, smoothed-out part of the screen grid current to compensate for its DC component in the primary vertical deflection yoke; it was variable to adjust the vertical picture position on the CRT screen. The screen grid delivered enough power even for an EHT winding on the horizontal deflection output transformer and for the 6.3V/0.2A heater of an RFG5 16-kV EHT rectifier. German 5+3-pin steel tube base with 2 unused pins, screen grid on top cap; compare US111

ET

• ET51 Trochotron, an electron-beam decade counter tube

—Special quality:

• E1T Decade counter tube with side-viewing, fluorescent-screen readout
• E80T/6218 (CV5724) Modulated, single-anode beam deflection tube for pulse generation up to 375 MHz; shock resistant up to 500 g

EW

• EW60 700 V_PIV, 400 mA, Gas-filled, half wave rectifier, 9-pin Loctal base with 2 unused pins

EY

• EY1 Half-wave rectifier, EY51 with a different base
• EY51/6X2 Half-wave rectifier, EY1 with a different base
• EY70 850 V half-wave rectifier, 4-pin all-glass pigtailed
• EY80 Half-wave rectifier, identical to PY80 except for heater ratings
• EY81/6R3 TV horizontal output booster diode
• EY82/6N3 Half-wave rectifier, PY82 with a different heater
• EY83 TV horizontal output booster diode, PY83 with a different heater
• EY84 Half-wave rectifier for operation at high altitudes
• EY86 Identical to DY86 except for heater ratings
• EY87 Identical to DY87 except for heater ratings
• EY88/6AL3 TV horizontal output booster diode, identical to LY88/20AQ3, PY88/30AE3 and XY88/16AQ3 except for heater ratings
• EY91 Half-wave rectifier
• EY500A/6EC4A Identical to PY500A except for heater ratings
• EY802 Identical to DY802 except for heater ratings

EYY

• EYY13 Dual power diode, separate cathodes

EZ

• EZ1 250 V, 50 mA Full-wave power rectifier for 6V car radios, identical to FZ1 except for heater ratings
• EZ2 Full-wave power rectifier
• EZ3 Full-wave power rectifier
• EZ4 Full-wave power rectifier
• EZ11 Full-wave power rectifier for vehicle equipment
• EZ12 Full-wave power rectifier
• EZ22 Full-wave power rectifier
• EZ35 Full-wave power rectifier
• EZ40 Full-wave power rectifier, GZ40 with a different heater
• EZ41 Full-wave power rectifier
• EZ80/6V4 Full-wave power rectifier
• EZ81/6CA4 Full-wave power rectifier
• EZ90/6X4 Full-wave power rectifier
• EZ91 Full-wave power rectifier
• EZ150 Full-wave power rectifier, separate cathodes

—Special quality:

• E90Z Full-wave power rectifier

F - 12.6 V heater

FL

• FL152 Identical to EL152 except for heater ratings

FZ

• FZ1 250 V, 50 mA Full wave power rectifier for 12V car radios, identical to EZ1 except for heater ratings

G - 5.0 V heater or misc.

GA

• GA560 Directly heated saturated-emission vacuum noise diode, all-glass, 3-pin base

GY

• GY11 Half-wave power rectifier, anode on top cap
• GY86 Half-wave, CRT EHT power rectifier, anode on top cap
• GY501 Half-wave, CRT EHT power rectifier, anode on top cap
• GY802 Half-wave, CRT EHT power rectifier, anode on top cap

GZ

• GZ30/5Z4-G/5AQ4 Full-wave power rectifier
• GZ32/5V4 Full-wave power rectifier
• GZ33 Full-wave power rectifier
• GZ34/5AR4 Full-wave power rectifier
• GZ37 Full-wave power rectifier
• GZ40 Full-wave power rectifier, EZ40 with a different heater
• GZ41 Full-wave power rectifier

H - 150 mA heater

HAA

• HAA91/12AL5 Dual diode with separate cathodes, miniature 7-pin base, identical to EAA91/6AL5, UAA91 and XAA91/3AL5 except for heater ratings

HABC

• HABC80/19T8 High-mu triode, triple diode (two on common cathode with triode, one with independent cathode), miniature 9-pin, used as an AF amplifier, AM detector and ratio detector in AC-powered post-war European AM/FM radios; identical to 5T8, 6T8, EABC80/6AK8, PABC80/9AK8 and UABC80/12AK8 except for heater ratings

HBC

• HBC90/12AT6 High-mu triode and common cathode dual diode, miniature 7-pin base, EBC90/6AT6 with a different heater
• HBC91/12AV6 High-mu AF triode and common cathode dual diode, for use in FM ratio detectors, miniature 7-pin base, EBC91/6AV6 with a different heater

HCC

• HCC85/17EW8 Dual triode for use as VHF oscillator/mixer up to 200 MHz, noval base, identical to ECC85/6AQ8, PCC85/9AQ8 and UCC85 except for heater ratings

HCH

• HCH81 Remote-cutoff triode/Hexode oscillator/mixer, noval base, UCH81/19D8 with a different heater

HF

• HF85 Remote-cutoff wideband RF Pentode, identical to EF85/6BY7 and XF85 except for heater ratings
• HF93/12BA6 Remote-cutoff pentode, miniature 7-pin base, EF93/6BA6 with a different heater
• HF94/12AU6 Sharp-cutoff RF/IF/AF pentode, miniature 7-pin base, identical to EF94/6AU6 and XF94/3AU6 except for heater ratings

HK

• HK90 Heptode pentagrid converter, miniature 7-pin, EK90 with a different heater

HL

• HL84 Audio power pentode, noval base, UL84 with a different heater
• HL90 Audio power pentode, miniature 7-pin, EL90 with a different heater
• HL92/50C5 Audio beam power pentode, miniature 7-pin, miniature 7-pin
• HL94/30A5 Audio power pentode, miniature 7-pin

HM

• HM34 Dual-sensitivity, "Magic Eye"-type tuning indicator, EM34 with different heater ratings, UM4 with different basing and heater ratings
• HM71 "Magic Fan"-type tuning indicator, octal B8D/F base, EM71 with a different heater
• HM85 "Magic Fan"-type tuning indicator, HM71 with noval B9A base, identical to EM85 and UM85 except for heater ratings

HY

• HY90/35W4 Half-wave rectifier, miniature 7-pin

I - 20 V heater

IF

• IF860 Long-life sharp-cutoff RF pentode for use as preamplifier in telecomms wide-area receivers, identical to EF860 except for heater ratings (95mA)

IL

• IL861 Long-life sharp-cutoff RF power pentode for use as output amplifier in telecomms wide-area transmitters, identical to EL861 except for heater ratings

K - 2.0 V heater

KA

• KA560 (6357) Gas-filled, directly heated noise diode for the 10 cm band, waveguide output, BA15d lamp base with anode top cap
• KA561 (6356) Gas-filled, directly heated noise diode for the 7.5 cm band, waveguide output, BA15d lamp base with anode top cap
• KA562 (6358) Gas-filled, directly heated noise diode for the 3 cm band, waveguide output, BA15d lamp base with anode top cap
• KA563 (6359) Gas-filled, directly heated noise diode for the 1.25 cm band, waveguide output, BA15d lamp base with anode top cap
• K50A (6358) Neon-filled, directly heated noise diode for the 3 cm band, waveguide output, BA15d lamp base with anode top cap
• K51A Neon-filled, directly heated noise diode for the 10 cm band, waveguide output, BA15d lamp base with anode top cap
• K81A Directly heated saturated-emission vacuum VHF noise diode, noval base

KB

• KB1 Directly heated dual diode with common cathode
• KB2 Indirectly heated dual diode with common cathode

KBC

• KBC1 Dual diode - triode
• KBC32 Dual diode - triode

KC

• KC1 Triode
• KC3 Triode
• KC4 Triode

KCF

• KCF30 Triode and remote-cutoff pentode, oscillator/mixer

KCH

• KCH1 Triode - octode pentagrid converter

KDD

• KDD1 1.5 W Dual power triode

KF

• KF1 RF/IF Pentode
• KF2 RF/IF Pentode
• KF3 Remote-cutoff RF/IF pentode
• KF4 RF/IF Pentode
• KF35 Remote-cutoff RF pentode

KH

• KH1 Heptode pentagrid converter

KK

• KK2 Octode pentagrid converter, KK32 with a different base
• KK32 Octode pentagrid converter, KK2 with a different base

KL

• KL1 Power pentode
• KL2 Power pentode
• KL4 Power pentode
• KL5 Power pentode
• KL35 340 mW Power pentode

KLL

• KLL32 1.2W Dual power pentode

KY

• KY80/U26 Half-wave rectifier. Noval base

L - 450 mA heater

LCF

• LCF80/6LN8 VHF mixer/oscillator triode/pentode, identical to ECF80/6BL8, PCF80/9A8, UCF80 and XCF80/4BL8 except for heater ratings
• LCF86/5HG8 VHF mixer/oscillator triode/pentode, identical to ECF86/6HG8, PCF86/7HG8, 8HG8 and XCF86/4HG8 except for heater ratings
• LCF201/5U9 Triode and pentode for use as IF amplifier and sync sep in TV receivers, decal base, identical to ECF201/6U9 and PCF201 except for heater ratings
• LCF801/5GJ7 Medium-mu triode and sharp-cutoff pentode for use as VHF mixer in TV receivers, noval base, identical to ECF801/6GJ7, PCF801/8GJ7 and XCF801/4GJ7 except for heater ratings
• LCF802/6LX8 Medium-mu triode and sharp-cutoff pentode for use as reactance and sinewave oscillator in TV receivers, noval base, identical to ECF802/6JW8, PCF802/9JW8 and 5JW8 except for heater ratings

LCL

• LCL84/10DX8 High-mu TV sync sep triode - sharp-cutoff CRT cathode drive power pentode, identical to ECL84/6DX8, PCL84/15DQ8 and XCL84/8DX8 except for heater ratings
• LCL85/10GV8 Triode - power pentode used in TV receivers for vertical timebase, generally as a multivibrator, with the pentode section doubling as one half of the multivibrator and the power output device, identical to ECL85/6GV8, PCL85/18GV8 and XCL85/9GV8 except for heater ratings

LF

• LF183/YF183/4EH7 Frame-grid, remote-cutoff IF pentode for use in TV receivers, identical to EF183/6EH7 and XF183/3EH7 except for heater ratings
• LF184/YF184/4EJ7 Frame-grid, sharp-cutoff IF pentode for use in TV receivers, identical to EF184/6EJ7 and XF184/3EJ7 except for heater ratings

LFL

• LFL200/11Y9 Sync sep pentode - CRT cathode drive power pentode, decal base; identical to EFL200/6Y9 and PFL200/16Y9 except for heater ratings

LL

• LL86/10CW5 Audio or CRT vertical deflection output power pentode, identical to EL86/6CW5, PL84/15CW5 and XL86/8CW5 except for heater ratings
• LL500/18GB5 CRT horizontal deflection beam power pentode, magnoval base, identical to EL500/6GB5, PL500/27GB5 and XL500/13GB5 except for heater ratings

LY

• LY88/20AQ3 TV horizontal output booster diode, identical to EY88/6AL3, PY88/30AE3 and XY88/16AQ3 except for heater ratings

M - 1.9 V heater

MC

• MC1 AF triode for use in audions

MF

• MF2 = RV2P800 RF pentode
• MF6 = RV2P7 RF pentode

N - 12.6 V heater

ND

• ND4 600 MHz, 10 W VHF power triode

NF

• NF2 Sharp-cutoff RF pentode; identical to AF7 and CF7 except for heater ratings
• NF3 Remote-cutoff RF pentode identical to CF2 except for heater ratings
• NF4 = RV12P4000 RF pentode
• NF6 = RV12P2000 RF pentode

O - No heater

Note: Philips sold a family of 150mA series heater tubes under this letter in South America: OBC3, OBF2, OCH4, OH4, OF1, OF5, OF9 and OM5

OZ

• OZ4 (0Z4) 30 ≤ I ≤ 75 mA, Full-wave gas rectifier with common cathode, 6-pin octal base

P - 300 mA heater

Note: Philips sold a family of 300mA series heater tubes under this letter in South America: PAB1, PBF2, PF9, PH4 and PM5

PABC

• PABC80/9AK8 High-mu triode, triple low-voltage diode (two on common cathode with triode, one with independent cathode). Miniature 9-pin noval base, used as an AF amplifier, AM detector and ratio detector in AC-powered post-war European AM/FM radios and TV receivers; identical to EABC80/6AK8, 5T8, 6T8/6T8A, HABC80/19T8, UABC80/12AK8 and DH719 except for heater ratings

PC

• PC86/4CM4 UHF Triode, EC86/6CM4 with a different heater
• PC88/4DL4 UHF Triode, EC88/6DL4 with a different heater
• PC92 RF Triode
• PC93 Triode
• PC95/4ER5 VHF Triode with variable mutual conductance, EC95 with a different heater
• PC96 Triode
• PC97/4FY5 Frame-grid VHF triode, identical to EC97/6FY5 and XC97 except for heater ratings
• PC900/4HA5 VHF Triode

PCC

• PCC82 Dual triode, identical to ECC82/12AU7 or XCC82 except for heater ratings
• PCC84/7AN7 Dual triode for VHF cascode amplifiers, noval base. Identical to ECC84/6CW7 and UCC84 except for heater ratings
• PCC85/9AQ8 Dual triode for use as VHF oscillator/mixer up to 200 MHz, noval base, identical to ECC85/6AQ8, HCC85/17EW8 and UCC85 except for heater ratings
• PCC88/7DJ8 Dual triode for use as cascode amplifiers, ECC88/6DJ8 with a different heater
• PCC89 Dual variable-mu triode for use as cascode amplifiers up to 220 MHz
• PCC189/7ES8 Dual VHF triode for cascode amplifiers; identical to ECC189/6ES8, XCC189/4ES8 and YCC189/5ES8 except for heater ratings

PCF

• PCF80/9A8 VHF mixer/oscillator triode/pentode, identical to ECF80/6BL8, LCF80/6LN8, UCF80 and XCF80/4BL8 except for heater ratings
• PCF82/9U8A Identical to ECF82/6U8 and XCF82 except for heater ratings
• PCF86/7HG8 VHF mixer/oscillator triode/pentode, identical to ECF86/6HG8, LCF86/5HG8, 8HG8 and XCF86/4HG8 except for heater ratings
• PCF200 Triode and pentode for use as IF amplifier in TV receivers, decal base, ECF200/6X9 with a different heater
• PCF201 Triode and pentode for use as IF amplifier and sync sep in TV receivers, decal base, identical to ECF201/6U9 and LCF201/5U9 except for heater ratings
• PCF800 (30C15) Triode - pentode
• PCF801/8GJ7 Triode and pentode for use as VHF mixer in TV receivers, noval base, identical to ECF801/6GJ7, LCF801/5GJ7 and XCF801/4GJ7 except for heater ratings
• PCF802/9JW8 Triode and pentode for use as reactance and sinewave oscillator in TV receivers, noval base, identical to ECF802/6JW8, LCF802/6LX8 and 5JW8 except for heater ratings
• PCF803 Triode - pentode
• PCF805/7GV7 Triode - pentode, ECF805 with a different heater
• PCF806 Triode - pentode
• PCF812 Triode - pentode

PCH

• PCH200/9V9 Triode - Hexode, for TV sync sep, ECH200 with a different heater

PCL

• PCL81 Identical to ECL81 except for heater ratings
• PCL82/16A8 AF triode - AF power pentode, identical to ECL82/6BM8, UCL82/50BM8 and XCL82 except for heater ratings
• PCL83 Triode - power pentode, ECL83 with a different heater
• PCL84/15DQ8 TV sync sep triode - CRT cathode drive power pentode, identical to ECL84/6DX8, LCL84/10DX8 and XCL84/8DX8 except for heater ratings
• PCL85/18GV8 Triode - power pentode used in TV receivers for vertical timebase, generally as a multivibrator, with the pentode section doubling as one half of the multivibrator and the power output device, identical to ECL85/6GV8, LCL85/10GV8 and XCL85/9GV8 except for heater ratings
• PCL86/14GW8 AF Triode - AF power pentode, used for audio amplification in European TV receivers, ECL86/6GW8 with a different heater
• PCL200 Triode - power pentode, ECL200 with a different heater
• PCL802 Triode - power pentode
• PCL805 Triode - power pentode, ECL805 with a different heater

PD

• PD500 25 kV Color CRT EHT shunt stabilizer triode. Identical to ED500 except for heater ratings
• PD510 25 kV Color CRT EHT shunt stabilizer triode

PF

• PF83 AF remote-cutoff pentode
• PF86 Pentode for use in Transitron circuits in TV receivers. Identical to EF86/6BK8 and UF86 except for heater ratings

PFL

• PFL200/16Y9 Sync sep pentode and CRT cathode drive power pentode, decal base; identical to EFL200/6Y9 and LFL200/11Y9 except for heater ratings

PL

• PL11 Power pentode
• PL33 CRT vertical deflection or AF output power pentode
• PL36/25E5 British high voltage high frequency switching pentode valve. Used in TV receivers for horizontal output and/or EHT generation up to c1964. Octal base, anode connection cap on the top of the valve. Last consumer electronics use DECCA series DR101, 202, 303, 404, 505, 606 monochrome receivers
• PL38 CRT horizontal deflection output power pentode, EL38/6CN6 with a different heater
• PL81/21A6 CRT horizontal deflection output power pentode
• PL82/16A5 CRT vertical deflection output power pentode
• PL83/15A6 (N309) CRT cathode drive power pentode
• PL84/15CW5 Audio or CRT vertical deflection output power pentode, identical to EL86/6CW5, LL86/10CW5 and XL86/8CW5 except for heater ratings
• PL95 AF Power pentode
• PL136 Color TV 110° horizontal deflection output power pentode, octal base
• PL500/28GB5 CRT horizontal deflection beam power pentode, magnoval base, identical to EL500/6GB5, LL500/18GB5 and XL500/13GB5 except for heater ratings
• PL502 CRT horizontal deflection output power pentode
• PL504 CRT horizontal deflection output power pentode, EL504 with a different heater
• PL508/17KW6 CRT vertical deflection output power pentode, EL508 with a different heater
• PL509/40KG6A CRT horizontal deflection output power pentode, EL509/6KG6A with a different heater
• PL511 CRT horizontal deflection output power pentode
• PL519 CRT horizontal deflection output power pentode, EL519 with a different heater
• PL521/29KQ6 CRT horizontal deflection output power pentode, separate pin for grid 3 to minimize "snivets", magnoval base, identical to 21KQ6 except for heater ratings
• PL802 CRT cathode drive output pentode, EL802 with a different heater
• PL805 CRT vertical deflection output power pentode, EL805 with a different heater

PLL

• PLL80 Dual AF power pentode

PM

• PM84 "Magic Band"-type tuning/level indicator, UM84/12FG6 with a different heater

PY

• PY31 Half-wave rectifier
• PY32 Half-wave rectifier
• PY33 Half-wave rectifier
• PY71 Half-wave rectifier
• PY80 EY80 with a different heater
• PY81 TV horizontal output booster diode
• PY82 EY82 with a different heater
• PY83 Half-wave rectifier, EY83 with a different heater
• PY88/30AE3 TV horizontal output booster diode, identical to EY88/6AL3, LY88/20AQ3 and XY88/16AQ3 except for heater ratings
• PY500A/42EC4A TV horizontal output booster diode. Identical to EY500A/6EC4A except for heater ratings
• PY800 TV horizontal output booster diode

PZ

• PZ30 Dual 200 mA rectifier diode, separate cathodes, octal base, for use as a voltage doubler in TV receivers

S - 1.9 V heater

SA

• SA100 Instrumentation rectifier diode up to 3 GHz
• SA101 Instrumentation rectifier diode
• SA102 Instrumentation rectifier diode

SD

• SD1A Shortwave power triode
• SD3 750 MHz, 3.5 W VHF power triode

SF

• SF1A Sharp-cutoff RF pentode, NF6 resp. RV12P2000 with a different heater

T - Custom heater

Note: Tungsram preceded the M-P designation with the letter T, as in TAD1 for AD1

TY

• TY86F 7.4 V, 77 mA heater version of the EY86 18-kV CRT EHT rectifier, for use as a hotfix in early-production Ferguson Radio Corporation TV receivers 306T and 308T where the horizontal-output transformer produced excessive heater voltage which destroyed the EY86's

U - 100 mA heater

Note: Philips sold a family of 100mA series heater tubes under this letter in South America: UBC1, UBF2, UF8 and UL1

UAA

• UAA11 Dual diode with separate cathodes
• UAA91 Dual diode with separate cathodes, miniature 7-pin base, identical to EAA91/6AL5, HAA91/12AL5 and XAA91/3AL5 except for heater ratings
• UAA171 Dual diode, separate cathodes, gnome tube

UABC

• UABC80/12AK8 High-mu triode, triple low-voltage diode (two on common cathode with triode, one with independent cathode). Miniature 9-pin noval base, used as an AF amplifier, AM detector and ratio detector in AC-powered post-war European AM/FM radios; identical to EABC80/6AK8, 5T8, 6T8/6T8A, HABC80/19T8, PABC80/9AK8 and DH719 except for heater ratings

UAF

• UAF21 Diode - remote-cutoff pentode, EAF21 with a different heater
• UAF41 Diode - pentode, EAF41 with a different heater
• UAF42/12S7 Diode - remote-cutoff RF/IF/AF pentode

UB

• UB41 Dual RF diode with separate cathodes, EB41 with a different heater

UBC

• UBC41 Dual diode - AF triode, EBC81 with a different basing
• UBC81 Dual diode - AF triode, EBC41 with a different basing

UBF

• UBF11 Dual diode - pentode, EBF11 with a different heater
• UBF15 Dual diode - pentode, EBF15 with a different heater
• UBF80/17C8 Dual diode - remote-cutoff pentode
• UBF89/19FL8 Dual diode - remote-cutoff pentode
• UBF171 Dual Diode and remote-cutoff RF/IF/AF pentode, gnome tube

UBL

• UBL1 Dual diode - power pentode
• UBL3 Dual diode - power pentode
• UBL21 Dual diode - power pentode
• UBL71 Dual diode - power pentode

UC

• UC92/9AB4 VHF triode for FM receicer frontends, single ECC81/12AT7 system, EC92/6AB4 with a different heater

UCC

• UCC84 Dual triode for VHF cascode amplifiers, noval base. Identical to ECC84/6CW7 and PCC84/7AN7 except for heater ratings
• UCC85 Dual triode for use as VHF oscillator/mixer up to 200 MHz, noval base, identical to ECC85/6AQ8, HCC85/17EW8 and PCC85/9AQ8 except for heater ratings
• UCC171 Dual triode, gnome tube

UCF

• UCF12 Triode - pentode, PCF12 with a different heater
• UCF80 VHF mixer/oscillator triode/pentode, identical to ECF80/6BL8, LCF80/6LN8, PCF80/9A8 and XCF80/4BL8 except for heater ratings
• UCF174 Triode and pentode, gnome tube

UCH

• UCH4 Triode/hexode oscillator/mixer, UCH5 or UCH21 with a different basing
• UCH5 Triode/hexode oscillator/mixer, UCH4 or UCH21 with a different basing
• UCH11 Triode/octode oscillator/mixer
• UCH21 Triode/hexode oscillator/mixer, UCH4 or UCH5 with a different basing
• UCH41 Remote-cutoff triode/hexode oscillator/mixer
• UCH42/14K7 Triode/hexode oscillator/mixer, Rimlock base, ECH42 with a different heater
• UCH43 Triode/hexode oscillator/mixer, low-microphonics version of UCH42; ECH43 with a different heater
• UCH71 Triode/hexode oscillator/mixer
• UCH81/19D8 Remote-cutoff triode/hexode oscillator/mixer, HCH81 with a different heater
• UCH171 Triode/remote-cutoff heptode Mixer, gnome tube

UCL

• UCL11 Triode - power pentode
• UCL81 Triode - power pentode, PCL81 with a different heater
• UCL82/50BM8 AF triode - AF power pentode, identical to ECL82/6BM8, PCL82/16A8 and XCL82 except for heater ratings
• UCL83 Triode - power pentode, PCL83 with a different heater

UEL

• UEL11 Tetrode - power tetrode, VEL11 with a different heater
• UEL51 Tetrode - power pentode
• UEL71 Tetrode - power pentode, EEL71 with a different heater
• UEL171 Remote-cutoff tetrode and 4-Watt power pentode, gnome tube

UF

• UF5 Pentode
• UF6 Pentode
• UF9 Remote-cutoff pentode
• UF11 Pentode
• UF14 Sharp-cutoff pentode, 8-pin base, identical to EF14 and VF14 except for heater ratings
• UF15 Pentode, EF15 with a different heater
• UF21 Pentode
• UF41 Remote-cutoff RF pentode, EF41 with a different heater
• UF42 Wide band pentode, EF42 with a different heater
• UF43 Wide band, remote-cutoff pentode, EF43 with a different heater
• UF80/19BX6 RF Pentode
• UF85/19BY7 Remote-cutoff RF pentode
• UF86 Identical to EF86 and PF86 except for heater ratings
• UF89 Remote-cutoff IF pentode
• UF172 RF/IF/AF Pentode, gnome tube
• UF174 Pentode, gnome tube
• UF175 Remote-cutoff RF/IF pentode, gnome tube
• UF176 VHF Pentode, gnome tube
• UF177 VHF Pentode, gnome tube

UFM

• UFM11 Remote-cutoff AF pentode and tuning indicator, EFM11 with a different heater

UH

• UH171 Sharp-cutoff heptode, gnome tube

UL

• UL2 Power pentode
• UL11 Power pentode
• UL12 Power pentode
• UL21 Power pentode
• UL41/45A5 AF power pentode
• UL44 Power pentode, identical to EL44 except for heater ratings
• UL71 Power pentode
• UL84/45B5 AF power pentode
• UL171 4-Watts Power pentode, gnome tube

ULL

• ULL80 Dual power pentode, ELL80 with a different heater

UM

• UM4/10M2 Dual-sensitivity, "Magic Eye"-type tuning indicator, UM34 with different basing; HM34 with different heater ratings
• UM11 Dual-sensitivity, "Magic Eye"-type tuning indicator made by Telefunken; EM11 with a different heater
• UM34 Dual-sensitivity, "Magic Eye"-type tuning indicator, UM4 with different basing; HM34 with different heater ratings
• UM35/10M2 Dual-sensitivity, "Magic Eye"-type tuning indicator
• UM80/19BR5 "Magic Fan"-type tuning indicator for AM receivers
• UM81 "Magic Fan"-type tuning indicator
• UM84/12FG6 "Magic Band"-type tuning/level indicator, PM84 with a different heater
• UM85 "Magic Fan"-type tuning indicator, noval base, identical to EM85 and HM85 except for heater ratings
• UM171 Dual-sensitivity tuning indicator, gnome tube

UQ

• UQ80 Nonode, EQ80/6BE7 with a different heater
• UQ171 Nonode, gnome tube

US

• US111 TV sync oscillator, a special relaxation oscillator pentode with the suppressor grid on a separate pin to act as a second control grid; German 5+3-pin steel tube base with 2 unused pins, screen grid on top cap. See ES111

UY

• UY1 Half-wave rectifier
• UY2 Half-wave rectifier
• UY3 Half-wave rectifier
• UY4 Half-wave rectifier
• UY11 Half-wave rectifier
• UY21 Half-wave rectifier
• UY31 Half-wave rectifier
• UY41/31A3 Half-wave rectifier
• UY42 Half-wave rectifier
• UY82/55N3 Half-wave rectifier
• UY85/38A3 Half-wave rectifier
• UY89 Half-wave rectifier
• UY92 Half-wave rectifier

V - 50 mA heater

Note: Vatea (United Incandescent Lamp and Electric Company, Budapest, Hungary) preceded the M-P designation with the letter V, as in VEL5 for EL5.

VBF

• VBF11 Dual diode and pentode, EBF11 with a different heater

VC

• VC1 Triode, 8-pin base with grid on top cap

VCH

• VCH11 Triode/hexode mixer, 8-pin base, ECH11 with a different heater

VCL

• VCL11 Triode - power pentode, 8-pin base

VEL

• VEL11 AF Tetrode - AF beam power tetrode, 8-pin base with E-tetrode grid on top cap, UEL11 with a different heater

VF

• VF3 Pentode, AF3 with a different heater
• VF7 Pentode, AF7 with a different heater
• VF14 Sharp-cutoff pentode, 81 V heater, 8-pin base, identical to EF14 and UF14 except for heater ratings
  • VF14M Selected VF14 in production until the end of the 1950s for use as a preamplifier in Neumann condenser microphones U-47 and U-48

VL

• VL1 1.6 W AF Pentode, 8-pin base, CL1 with a different heater
• VL4 4 W AF Pentode, 8-pin base, CL4 with a different heater

VY

• VY1 60 mA Half-wave rectifier, 8-pin base
• VY2 35 mA Half-wave rectifier, 8-pin base

X - 600 mA heater

XAA

• XAA91/3AL5 Dual diode with separate cathodes, miniature 7-pin base, identical to EAA91/6AL5, HAA91/12AL5 and UAA91 except for heater ratings

XC

• XC95 Triode, PC95 with a different heater
• XC97 Frame-grid VHF triode, identical to EC97/6FY5 and PC97/4FY5 except for heater ratings

XCC

• XCC82 Dual triode, identical to ECC82/12AU7 or PCC82 except for heater ratings
• XCC189/4ES8 Dual VHF triode for cascode amplifiers; identical to ECC189/6ES8, PCC189/7ES8 and YCC189/5ES8 except for heater ratings

XCF

• XCF80/4BL8 VHF mixer/oscillator triode/pentode, identical to ECF80/6BL8, PCF80/9A8, LCF80/6LN8 and UCF80 except for heater ratings
• XCF82 Triode and pentode, identical to ECF82/6U8 and PCF82/9U8A except for heater ratings
• XCF801/4GJ7 Triode and pentode for use as VHF mixer in TV receivers, noval base, identical to ECF801/6GJ7, LCF801/5GJ7 and PCF801/8GJ7 except for heater ratings

XCH

• XCH81 Triode/hexode oscillator/mixer, ECH81/6AJ8 with a different heater

XCL

• XCL82 AF triode - AF power pentode, identical to ECL82/6BM8, PCL82/16A8 and UCL82/50BM8 except for heater ratings
• XCL84/8DX8 TV sync sep triode - CRT cathode drive power pentode, identical to ECL84/6DX8, LCL84/10DX8 and PCL84/15DQ8 except for heater ratings
• XCL85/9GV8 Triode and power pentode for TV vertical output. Identical to ECL85/6GV8, LCL85/10GV8 and PCL85/18GV8 except for heater ratings

XF

• XF80 RF/IF/Video pentode, identical to EF80/6BX6 and UF80 with a different heater, noval base
• XF85 Remote-cutoff wideband RF pentode, noval base, identical to EF85/6BY7 and HF85 except for heater ratings
• XF94/3AU6 Sharp-cutoff RF/IF/AF Pentode, miniature 7-pin base, identical to EF94/6AU6 and HF94/12AU6 except for heater ratings
• XF183/3EH7 Frame-grid, remote-cutoff IF pentode for use in TV receivers, identical to EF183/6EH7 and LF183/YF183/4EH7 except for heater ratings
• XF184/3EJ7 Frame-grid, sharp-cutoff IF pentode for use in TV receivers, identical to EF184/6EJ7 and LF184/YF184/4EJ7 except for heater ratings

XL

• XL36/13CM5 Audio or CRT horizontal deflection output power pentode, EL36/6CM5 with a different heater
• XL84 Power pentode, EL84 with a different heater
• XL86/8CW5 Audio or CRT vertical deflection output power pentode, identical to EL86/6CW5, LL86/10CW5 and PL84/15CW5 except for heater ratings
• XL500/13GB5 CRT horizontal deflection beam power pentode, magnoval base, identical to EL500/6GB5, LL500/18GB5 and PL500/27GB5 except for heater ratings

XY

• XY88/16AQ3 TV horizontal output booster diode, identical to EY88/6AL3, LY88/20AQ3 and PY88/30AE3 except for heater ratings

Y - 450 mA heater

YCC

• YCC189/5ES8 Dual VHF triode for cascode amplifiers; identical to ECC189/6ES8, PCC189/7ES8 and XCC189/4ES8 except for heater ratings

YF

• YF183/LF183/4EH7 Frame-grid, remote-cutoff IF pentode for use in TV receivers, identical to EF183/6EH7 and XF183/3EH7 except for heater ratings
• YF184/LF184/4EJ7 Frame-grid, sharp-cutoff IF pentode for use in TV receivers, identical to EF184/6EJ7 and XF184/3EJ7 except for heater ratings

Z - Cold cathode tube

Notes: Special-quality cold-cathode "Z" tubes had a different function letter scheme.

See also the professional tubes under Z

ZA

• Z960A Cold-cathode surge protector for receiver frontends

ZC

• Z302C Unusual decade Counter Dekatron, a counterclockwise-only decade counter tube with separate odd and even extinguishing electrodes except "0", which is tied to a -300V supply so reaching the terminal count produces a negative spike on the anode voltage which can be used to advance the next counter stage with no intermediate active components
• Z303C Neon-filled, 4 kHz bidirecional decade Counter Dekatron
• Z563C Neon-filled 4 kHz bidirecional decade Counter Dekatron
• Z565C 4 kHz Bidirecional decade Counter Dekatron
• Z573C Neon-filled 4 kHz bidirecional decade Counter Dekatron with aux anodes for direct control of Nixie tubes

ZE

• Z862E Noble-gas filled, cold-cathode electrometer tube, control current 10 pA, silicone-coated envelope for isolation, guard ring, envelope inside radioactively coated for a constant ignition voltage

ZM

• ZM11 Neon-filled digital indicator tube, 21 mm character height, top-viewing, showing a cross with a central dot and independent arms, for use in industrial control panels
• ZM13 Neon-filled digital indicator tube, 21 mmCH, top-viewing, showing a vertical line and a circle with a small gap, for use in industrial control panels
• ZM13U Neon-filled digital indicator tube, 21 mmCH, top-viewing, showing a vertical line and a circle, for use in industrial control panels
• ZM14 Neon-filled digital indicator tube, 21 mmCH, top-viewing, showing a vertical line, a circle, a triangle and a three-winged star, for use in industrial control panels
• Z510M  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 15.5 mmCH, top-viewing, no decimal point
• Z520M See ZM1020
• Z521M See ZM1021
• Z522M See ZM1040
• Z550M See ZM1050
• Z560M Z5600M with a red contrast filter coating
• Z561M Z5610M with a red contrast filter coating
• Z566M Z5660M with a red contrast filter coating
• Z567M Z5670M with a red contrast filter coating
• Z568M Z5680M with a red contrast filter coating
• Z570M Z5700M with a red contrast filter coating
• Z571M Z5710M with a red contrast filter coating
• Z573M Z5730M with a red contrast filter coating
• Z574M Z5740M with a red contrast filter coating
• Z580M Z5800M with a red contrast filter coating
• Z581M Z5810M with a red contrast filter coating
• Z590M Z5900M with a red contrast filter coating
• Z870M Z8700M with a red contrast filter coating
• Z5200M See ZM1022
• Z5220M See ZM1042
• Z5600M  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 15.5 mmCH, top-viewing, no decimal point
• Z5610M  A V Ω + - ~ % W  Neon-filled digital indicator tube, 15.5 mmCH top-viewing, for use in digital multimeters
• Z5660M  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 30 mmCH, side-viewing, no decimal point
• Z5670M  + - ~  Neon-filled digital indicator tube, 18/30 mmCH side-viewing
• Z5680M  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 50 mmCH side-viewing, no decimal point
• Z5700M  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 13 mmCH side-viewing, no decimal point
• Z5710M  + - ~  Neon-filled digital indicator tube, 10.5/13 mmCH side-viewing
• Z5730M  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 13 mmCH side-viewing, right decimal points
• Z5740M  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 13 mmCH side-viewing, left decimal points
• Z5800M  T G M k m µ n p  Neon-filled digital indicator tube, 13 mmCH side-viewing
• Z5810M  A F H S V Ω Hz s  Neon-filled digital indicator tube, 13 mmCH side-viewing, for use in digital multimeters
• Z5900M  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 10 mmCH side-viewing, both left and right decimal points
• Z8700M  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 10 mmCH side-viewing, no decimal point, 5 dual cathodes and separate odd/even anode compartments for biquinary multiplexing

Note: More Nixie tubes under professional - ZM and other letter - GR

ZS

• Z502S Neon-filled, 4 kHz max. decade Counter/Selector Dekatron
• Z504S (ZM1070, 8433) Neon-filled, 5 kHz max. decade Counter/Selector Dekatron
• Z505S (ZM1060) Argon-filled, 50 kHz max. decade Counter/Selector Dekatron
• Z562S Neon-filled, 4 kHz max. decade Counter/Selector Dekatron, envelope inside radioactively coated for a constant ignition voltage
• Z564S 25 kHz max. Decade Counter/Selector Dekatron, envelope inside radioactively coated for a constant ignition voltage
• Z572S Neon-filled, 5 kHz max. decade Counter/Selector Dekatron, aux anodes to directly drive Nixie tubes, envelope inside radioactively coated for a constant ignition voltage

ZT

• Z50T Subminiature, 6 mA_avg, 24 mA_peak, Gas-filled, cold-cathode trigger triode, 1 starter, 3-pin all-glass pigtailed, for use as switch in bang–bang controllers
• Z300T (PL1267) 25 mA_avg, 100 mA_peak, Gas-filled, cold-cathode DC trigger triode, one starter, octal base
• Z900T/5823 25 mA_avg, 100 mA_peak, Gas-filled, cold-cathode AC trigger triode, one starter, miniature 7-pin base

ZU

• Z70U/7710 Subminiature, 3 mA_avg, 12 mA_peak, Gas-filled, cold-cathode DC trigger tetrode, one starter and a primer electrode, positive starter voltage, 4-pin all-glass pigtailed
• Z71U/7711 Subminiature, 7 mA_avg, 12 mA_peak, Gas-filled, cold-cathode DC trigger tetrode, two starters, positive starter voltage, low impedance for audio frequencies, 4-pin all-glass pigtailed
• Z700U Subminiature, 4 mA_avg, 16 mA_peak, Gas-filled, cold-cathode DC trigger tetrode, one starter and a primer electrode, positive starter voltage, all-glass pigtailed, for use in Dekatron circuits up to 2 – 5 kHz
• Z701U Subminiature, Gas-filled, cold-cathode trigger tetrode, all-glass pigtailed
• Z800U 2.5 mA_avg, 10 mApeak, Gas-filled, cold-cathode DC trigger tetrode, one starter and a primer electrode, positive starter voltage, noval base, for voltage control, sensitive relay circuits and timers
• Z801U 2.5 mA_avg, 10 mApeak, Gas-filled, cold-cathode DC trigger tetrode, one starter and a primer electrode, negative starter voltage, noval base, for use with Geiger-Müller tubes
• Z803U/6779 25 mA_avg, 100 mA_peak, Gas-filled, cold-cathode DC trigger tetrode, one starter and a primer electrode, positive starter voltage, noval base, for voltage control, sensitive relay circuits and timers
• Z804U/7713 5 mA_avg, 25 mA_peak, Gas-filled, cold-cathode AC trigger tetrode, one starter and a primer envelope coating, negative starter voltage, noval base, direct operation from a 200...250VAC mains grid but should be triggered only while U_A > 0
• Z805U/7714 5 mA_avg, 25 mA_peak, Gas-filled, cold-cathode AC trigger tetrode, one starter, two primers and separate cathode and anode shields on individual pins, positive starter voltage, noval base, direct operation from a 200...250VAC mains grid, for relay drivers, timers, photoelectric controls, etc.

ZW

• Z70W/7709 4 mA, Gas-filled, cold-cathode DC trigger pentode, two starters and a primer electrode, positive starter voltage, 5-pin all-glass pigtailed, for use in bidirectional counters
• Z660W (GR43) 12 mA_avg, 50 mA_peak, Gas-filled, cold-cathode DC trigger pentode, two starters and a primer electrode, positive starter voltage, 5-pin all-glass pigtailed, envelope inside radioactively coated for a constant ignition voltage, for use in bidirectional counters
• Z661W (ZC1010) 8 mA_avg, 50 mA_peak, Gas-filled, cold-cathode AC trigger pentode, two starters and a primer electrode, positive starter voltage, 5-pin all-glass pigtailed, envelope inside radioactively coated for a constant ignition voltage, for use in bidirectional counters
• Z700W 4 mA, Gas-filled, cold-cathode DC trigger pentode, two starters and a primer electrode, positive starter voltage, 5-pin all-glass pigtailed, for use in bidirectional counters
• Z806W Gas-filled, cold-cathode trigger tetrode, one starter and dual primer, noval base, used in elevator controls
• Z865W 25 mA_avg, 200 mA_peak Gas-filled, cold-cathode AC/DC trigger tetrode, one starter and a primer electrode, low positive starter voltage for transistorized circuits, 9-pin base, envelope inside radioactively coated for a constant ignition voltage, for use as a relay driver

ZX

• Z860X 40 mA_avg, 200 mA_peak, Gas-filled, cold-cathode DC trigger pentode, two starters, a primer electrode and an internal shield, positive starter voltage, noval base, envelope inside radioactively coated for a constant ignition voltage, for use in counters
• Z861X 40 mA_avg, 200 mA_peak, Gas-filled, cold-cathode AC trigger pentode, two starters, a primer electrode and an internal shield, positive starter voltage, noval base, envelope inside radioactively coated for a constant ignition voltage, for use in counters
• Z863X 40 mA_avg, 200 mA_peak, Gas-filled, cold-cathode DC trigger pentode, two starters, a primer electrode and an internal shield, negative starter voltage, noval base, envelope inside radioactively coated for a constant ignition voltage, for use in counters

List of Pro Electron professional tubes

Note: Typecode explained above.

X - Electro-optical devices

XA

• XA1003 Phototube, caesium-on-oxydated-silver cathode, 2-pin all-glass pigtailed

XG

• XG2000 Image converter for x-ray diagnostics

XL

• XL7900 Vibrating-capacitor chopper front end for dosimeters, electrometers, pH meters etc., Magnoval base with gold-plated pins

XM

• XM1000 Nimo tube, directly heated cathode-ray 1-digit numeric display tube, decimal points on both sides, hence 12 stenciled electron guns, top-viewing, green, 15 mm high Futura Medium font, oval envelope for easy horizontal stacking, 14-pin base

XP

• XP1000 10-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal (14-pin) base
• XP1001 10-stage photomultiplier for gamma ray scintillation spectrometry, Sb-Cs cathode, Ag-Mg-O-Cs dynodes
• XP1002 10-stage photomultiplier, blue/green/yellow/orange-sensitive Sb-Na-K-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
• XP1003 10-stage photomultiplier with quartz window, UV/blue/green/yellow/orange-sensitive Sb-Na-K-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
• XP1004 10-stage photomultiplier with quartz window, UV/blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
• XP1005 10-stage Ag-O-Cs (800±100 nm) photomultiplier, IR/red-sensitive Ag-O-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
• XP1010 10-stage photomultiplier for r-ray and gamma ray scintillation spectrometry, selected 150AVP for low noise and resolution, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, duodecal (12-pin) base
• XP1011 10-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, shock and vibration-proof, duodecal base
• XP1020 12-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, 100 O output, duodecal (20-pin) base
• XP1021 12-stage photomultiplier, UV/blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, 50 O output, duodecal base
• XP1023 12-stage photomultiplier with quartz window Sb-Cs cathode, Ag-Mg-O-Cs dynodes, UV/blue-sensitive, 50 O output, duodecal base
• XP1030 10-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal (14-pin) base
• XP1031 10-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, for gamma ray scintillation spectrometry
• XP1032 10-stage photomultiplier with 3 mm quartz window, UV/blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
• XP1033 10-stage photomultiplier with 10 mm quartz window, UV/blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, diheptal base
• XP1040 14-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, concave window, duodecal base
• XP1110 Photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes
• XP1111 Photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, pigtails
• XP1113 6-stage Photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes
• XP1114 4-stage Photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes
• XP1115 Photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, pigtails, shock and vibration-proof
• XP1116 Photomultiplier, red-sensitive Ag-O-Cs cathode, Ag-Mg-O-Cs dynodes, shock and vibration-proof
• XP1117 9-stage photomultiplier, blue/green/yellow/orange-sensitive Sb-Na-K-Cs cathode, Ag-Mg-O-Cs dynodes
• XP1118 Photomultiplier with quartz window, UV/blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes
• XP1120 17-stage photomultiplier for x-ray (λ > 200 pm) or UV (λ < 150 nm) photon counting in a high-vacuum environment, Nickel cathode, Cu-Be-O dynodes, coaxial outputs, built-in resistor ladder
• XP1121 17-stage photomultiplier for ion (> 10 keV) or electron (0.1...10 keV) photon counting in a high-vacuum environment, Cu-Be-O cathode and dynodes, coaxial outputs, built-in resistor ladder
• XP1122 17-stage photomultiplier for x-ray (λ > 200 pm) or UV (λ < 150 nm) photon counting in a high-vacuum environment, Nickel cathode, Cu-Be-O dynodes, coaxial outputs, built-in resistor ladder
• XP1123 17-stage photomultiplier for ion (> 10 keV) or electron (0.1...10 keV) photon counting in a high-vacuum environment, Cu-Be-O cathode and dynodes, coaxial outputs, built-in resistor ladder
• XP1130 17-stage photomultiplier for x-ray (λ > 200 pm) or UV (λ < 150 nm) photon counting in a high-vacuum environment, Nickel cathode, Cu-Be-O dynodes, coaxial outputs, built-in resistor ladder
• XP1131 17-stage photomultiplier for ion (> 10 keV) or electron (0.1...10 keV) photon counting in a high-vacuum environment, Cu-Be-O cathode and dynodes, coaxial outputs, built-in resistor ladder
• XP1140 6-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, fast, diheptal base
• XP1141 7-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, fast, diheptal base
• XP1180/52AVP 10-stage photomultiplier, blue-sensitive Sb-Cs cathode, Ag-Mg-O-Cs dynodes, fast, diheptal base
• XP1240 Photomultiplier

XQ

• XQ1023 - Camera tube
• XQ1029R - Camera tube
• XQ1032 - 1" Vidicon; magnetic focusing and deflection
• XQ1053 - Camera tube
• XQ1072 - 1" Plumbicon
• XQ1073 - XQ1072 with higher resolution and improved low level contrast
• XQ1200 - Vidicon, silicon target
• XQ1270 - ⅔" Vidicon; Overall length 108mm (4¼")
• XQ1272 - Camera tube
• XQ1274 - ⅔" Newvicon, magnetic focussing and deflection, zinc telluride, zinc selenide target
• XQ1275 - Vidicon, silicon target
• XQ1276 - XQ1274 with high sensitivity into the near infrared
• XQ1277 - XQ1275 with high sensitivity into the near infrared
• XQ1278 - XQ1275 with better geometry and uniform signal
• XQ1285 - 1" Vidicon; magnetic focusing and deflection, precision electron gun
• XQ1290 - Camera tube
• XQ1293 - Camera tube
• XQ1300 - Saticon Camera Tube
• XQ1340 - Low-light vidicon
• XQ1371 - Resistron camera tube
• XQ1380 - XQ1274 with radiation resistant (anti-browning) faceplate
• XQ1381 - ⅔" Newvicon; electrostatioc focusing and magnetic deflection with radiation-resistant (anti-browning) faceplate
• XQ1395 - High-resolution Resistron camera tube
• XQ1410B/G/R - Plumbicon with color filter for color TV broadcast
• XQ1412 - 6/5" Plumbicon; low lag, unity gamma matched to P20 phosphor
• XQ1413B/G/R - Plumbicon with color filter for color TV broadcast
• XQ1415B/G/R - Plumbicon with color filter for color TV broadcast
• XQ1427 - ⅔" Plumbicon; low lag
• XQ1427B/G/R - Plumbicon with color filter for color TV broadcast
• XQ1430B/G/R - Plumbicon with color filter for color TV broadcast
• XQ1435B/G/R - Plumbicon with color filter for color TV broadcast
• XQ1440 - 1" Newvicon, separate mesh, zinc telluride, zinc selenide target
• XQ1500B/G/R - Plumbicon with color filter for color TV broadcast
• XQ1505B/G/R - Plumbicon with color filter for color TV broadcast
• XQ1560 - 1" Saticon
• XQ1565 - 1" Saticon
• XQ1570 - 1" Saticon
• XQ1575 - 1" Saticon
• XQ1585 - 1" Saticon
• XQ1600 - ½" Vidicon; separate mesh, electrostatic focusing and magnetic deflection
• XQ1601 - ½" Newvicon; separate mesh, electrostatic focusing and magnetic deflection
• XQ2070/02B/G/R - Plumbicon with color filter for color TV broadcast
• XQ2070/05B/G/R - Plumbicon with color filter for color TV broadcast
• XQ2075/02B/G/R - Plumbicon with color filter for color TV broadcast
• XQ2075/05B/G/R - Plumbicon with color filter for color TV broadcast
• XQ2172 - 1" Plumbicon; wide dynamic range matched to digital radiography applications
• XQ2182 - 1" Plumbicon; wide dynamic range matched to digital radiography applications
• XQ2427B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3070/02B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3070/05B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3075/02B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3075/05B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3427B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3430B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3435B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3440B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3445B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3457B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3467B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3477B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3487B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3550B/G/R - Plumbicon with color filter for color TV broadcast
• XQ3555B/G/R - Plumbicon with color filter for color TV broadcast
• XQ4187B/G/R - Plumbicon with color filter for color TV broadcast
• XQ4502 - 2" Plumbicon; Highest resolution, low lag
• XQ5002 - 2" Plumbicon; Electrostsatic deflection for improved corner resolution, low output capacitance
• XQ7002 - 1" Plumbicon; Low output capacitance
• XQ8002 - 1" Plumbicon
• XQ9002 - 1" Plumbicon

XR

• XR1000 Monoscope, test pattern specified by suffix

XX

• XX1000 2-stage image intensifier
• XX1010 Image intensifier
• XX1020 Image intensifier
• XX1030 Image intensifier
• XX1050 Image intensifier
• XX1060 Image intensifier
• XX1066 1. Gen. 3-stage image intensifier
• XX1140 1. Gen. 3-stage image intensifier
• XX1190 1. Gen. inverter, 1-stage image intensifier
• XX1192 1. Gen. inverter, 1-stage image intensifier
• XX1200 1. Gen. inverter, 1-stage image intensifier
• XX1211 1. Gen. inverter, 3-stage image intensifier
• XX1270 1. Gen. inverter, 2-stage image intensifier
• XX1400 2. Gen. inverter, 1-stage image intensifier
• XX1430 1. Gen. inverter, 1-stage image intensifier
• XX1510 1. Gen. 3-stage image intensifier
• XX1610 2. Gen. image intensifier
• XX1800 2. Gen. proximity focused, 1-stage image intensifier

Y - Vacuum tubes

YA

• YA1000 - 5 kV, 5mA, Directly heated saturated-emission diode with pure-metal cathode for use in RMS converters of AC voltage/current stabilizer circuits, noval base

YD

• YD1000 - 120 kW, Water-cooled RF power triode
• YD1001 - 120 kW, Air-cooled RF power triode
• YD1012 - 360 kW, Vapor-cooled RF power triode
• YD1130 - 580 W, Air-cooled, linear RF/AF power triode
• YD1252 (RS 2051 V) - 420 kW, Water-cooled, modulator power triode
• YD1300 - 35 W, Air-cooled, UHF power triode
• YD1301 - 50 W, Air-cooled, UHF power triode
• YD1302 - 55 W, Air-cooled, UHF power triode
• YD1332 - 250 W, Air-cooled, UHF power triode
• YD1333 - 100 W, Air-cooled, UHF power triode
• YD1334 - 110 W, Air-cooled, UHF power triode
• YD1335 - 550 W, Air-cooled, UHF power triode
• YD1336 - 220 W, Air-cooled, UHF power triode
• YD1342 - 30 MHz, 530 kW, Water-cooled RF power triode
• YD1352S - 5 MHz, 3 kW, Water-cooled, magnetically beamed RF power triode

YG

• YG1000 - Directly heated electrometer tetrode with oxide cathode and space charge grid, grid current ≤600 fA, magnoval base with input grid on top cap

YH

• YH1000 - Traveling-wave tube
• YH1050 - Traveling-wave tube
• YH1110 - Traveling-wave tube
• YH1120 - Traveling-wave tube, >3 GHz
• YH1131 - Traveling-wave tube, >3 GHz
• YH1150 - Traveling-wave tube
• YH1160 - Traveling-wave tube, >3 GHz
• YH1181 - Traveling-wave tube, >3 GHz
• YH1190 - Traveling-wave tube, >3 GHz
• YH1200 - Traveling-wave tube, >3 GHz

YJ

• YJ1000 - Indirectly heated, 2.5 kW Magnetron for use as a pulsed X-band oscillator between 9.19 and 9.32 GHz

YK

• YK1000 - Water-cooled, permanent-magnet 11 kW UHF linear-beam Klystron for use in TV transmitters between 400 and 620 MHz
• YK1004 - Water-cooled, permanent-magnet 11 kW UHF linear-beam Klystron for use in TV transmitters between 610 and 790 MHz
• YK1005 - Water-cooled, permanent-magnet 11 kW UHF linear-beam Klystron for use in TV transmitters between 470 and 860 MHz
• YK1046 - 35 mW X-band Klystron, 9.16 to 9.34 GHz
• YK1151 - Forced-air cooled, permanent-magnet 25 kW UHF linear-beam Klystron for use in TV transmitters between 470 and 860 MHz
• YK1190 - Water-cooled 40 kW UHF linear-beam Klystron for use in TV transmitters between 470 and 610 MHz
• YK1191 - Water-cooled 40 kW UHF linear-beam Klystron for use in TV transmitters between 590 and 720 MHz
• YK1192 - Water-cooled 40 kW UHF linear-beam Klystron for use in TV transmitters between 710 and 860 MHz

YL

• YL1000/8463 - RF power pentode
• YL1020/8118 - See QQZ03/20
• YL1030 - See QQZ06/40
• YL1050 - RF power tetrode
• YL1060/7854 - See QQE06/40
• YL1070/8117 - RF power pentode
• YL1071 - YL1070 with a different heater
• YL1080/8348 - RF power pentode
• YL1120 - RF power tetrode
• YL1130/8408 - RF power pentode
• YL1150/8579 - RF power pentode
• YL1190/8580 - RF power pentode
• YL1200 - See PE1/100
• YL1210 - QQE03/12 with a different heater
• YL1220 - QQE02/5 with a different heater
• YL1240/8458 - RF power pentode
• YL1250/8505 - RF power pentode
• YL1270/8581 - RF power pentode
• YL1290 - QE08/200 with a different heater
• YL1310/8603 - RF power pentode
• YL1360 - QQE04/5 with a different heater
• YL1570 (RS 1084 CJ) - RF power tetrode

Z - Gas-filled tubes

Note: See also standard M-P tubes under Z

ZA

• ZA1000 Neon-filled, coaxial, tritium-primed (half-life: 12.32 years), sputtered-molybdenum cold-cathode switching diode, meshed cylinder anode, all-glass pigtailed
• ZA1001 Neon-filled, coaxial, tritium-primed, sputtered-molybdenum cold-cathode switching diode with traces of heavy gas (krypton/xenon) for slow de-ionization, e.g. for low-frequency relaxation oscillators; meshed cylinder anode, all-glass pigtailed
• ZA1002 Neon-filled, coaxial, tritium-primed, sputtered-molybdenum cold-cathode switching diode, large difference between burning and ignition voltage, meshed cylinder anode, 3-pin all-glass pigtailed
• ZA1003 Neon-filled, coaxial, tritium-primed, sputtered-molybdenum cold-cathode switching diode for use as indicator tube in transistorized circuits, meshed cylinder anode, 3-pin all-glass pigtailed
• ZA1004 Neon-filled, coaxial, tritium-primed, sputtered-molybdenum cold-cathode switching diode, small difference between burning and ignition voltage, for use as indicator tube in transistorized circuits or as 86.4 V Voltage reference, meshed cylinder anode, 3-pin all-glass pigtailed
• ZA1005 Neon-filled, coaxial, tritium-primed, sputtered-molybdenum cold-cathode switching diode for use like a DIAC in thyristor circuits, meshed cylinder anode, 2-pin all-glass pigtailed

ZC

• ZC1010 (Z661W) 8 mA_avg, 50 mA_peak, Gas-filled, cold-cathode AC trigger pentode, two starters and a primer electrode, positive starter voltage, 5-pin all-glass pigtailed, envelope inside radioactively coated for a constant ignition voltage, for use in bidirectional counters
• ZC1040 25 mA, Gas-filled, cold-cathode AC trigger tetrode, one starter and a primer electrode, positive starter voltage, noval base
• ZC1050 2 mA, Gas-filled, cold-cathode, luminiscent trigger tetrode, one starter and a primer, 300 mlm light output for use as self-displaying shift register cells in large-format, crawling-text dot-matrix displays; all-glass pigtailed
• ZC1060 20 mA_avg, 5 kA_peak, Gas-filled, cold-cathode, high-current trigger triode for e.g. capacitor discharge circuits. One external (capacitive) starter electrode

ZM

• ZM1000  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 14 mm character height side-viewing, left decimal point
• ZM1000R ZM1000 with a red contrast filter coating
• ZM1001  + - ~ X Y Z  Neon-filled digital indicator tube, 14mmCH side-viewing, for use with ZM1000
• ZM1001R ZM1001 with a red contrast filter coating, for use with ZM1000R
• ZM1002  ns μs ms s Hz kHz MHz  Neon-filled digital indicator tube, 13mmCH side viewing, for use with ZM1000 in digital frequency counters
• ZM1003  1 - +  Neon-filled digital indicator tube, 14mmCH side-viewing, for use with ZM1000
• ZM1005  0 1 2 3 4 5 6 7 8 9  Long-life neon-filled digital indicator tube, 14mmCH side-viewing, left decimal point, multiplex-capable
• ZM1005R ZM1005 with a red contrast filter coating
• ZM1006  1 2 3 4 5 6  Neon-filled digital indicator tube, side-viewing, left and right decimal point, for use in TV receivers
• ZM1008  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 14mmCH side-viewing
• ZM1010  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 14mmCH side-viewing, left decimal point
• ZM1012  0 1 2 3 4 5 6 7 8  Neon-filled digital indicator tube, 14mmCH side-viewing
• ZM1015  0 1 2 3 4 5 6 7 8  Neon-filled digital indicator tube, 14mmCH side-viewing
• ZM1020 (Z520M) ZM1022 with a red contrast filter coating
• ZM1021 (Z521M) ZM1023 with a red contrast filter coating, for use with ZM1020
• ZM1022  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 15.5mmCH top-viewing, no decimal point
• ZM1023  A V Ω % + - ~  Neon-filled digital indicator tube, 15.5mmCH top-viewing, for use with ZM1022 in digital multimeters
• ZM1024 ZM1025 with a red contrast filter coating, for use with ZM1020
• ZM1025  c/s Kc/s Mc/s μs ms ns s  Neon-filled digital indicator tube, 15.5mmCH top-viewing, for use with ZM1022 in digital frequency counters
• ZM1030 ZM1032 with a red contrast filter coating
• ZM1031 ZM1031/01 without the  ~ 
• ZM1031/01 ZM1033/01 with a red contrast filter coating, for use with ZM1030
• ZM1032  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 15.5mmCH side-viewing, no decimal point, 5 dual cathodes and separate odd/even anode compartments for biquinary multiplexing
• ZM1033/01  + - ~  Neon-filled digital indicator tube, 15.5mmCH side-viewing, separate anode compartment for  + , for use with ZM1032
• ZM1040 (Z522M) ZM1042 with a red contrast filter coating
• ZM1041 ZM1043 with a red contrast filter coating, for use with ZM1040
• ZM1041S ZM1043S with a red contrast filter coating, for use with ZM1040
• ZM1042 (Z5220M)  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 30mmCH side-viewing, no decimal point
• ZM1043  + -  Neon-filled digital indicator tube, 30mmCH side-viewing, for use with ZM1042
• ZM1043S  Y X + W U Z -  Neon-filled digital indicator tube, 30mmCH side-viewing, for use with ZM1042
• ZM1047 ZM1049 with a red contrast filter coating, for use with ZM1040
• ZM1049  T F S N Z Y G H M X  Neon-filled digital indicator tube, side-viewing, for use with ZM1042 in numerical control systems

ZM1070

• ZM1050 (Z550M, 8453) Neon-filled digital indicator tube, top-viewing, dekatron-type readout with common anode and common cathodes, pulsating anode voltage, controlled by 5-volts sensitive starter electrodes, for transistorized circuits
• ZM1060 (Z505S) Argon-filled, 50 kHz decade Counter/Selector Dekatron
• ZM1070 (Z504S, 8433) Neon-filled, 5 kHz decade Counter/Selector Dekatron
• ZM1080 ZM1082 with a red contrast filter coating
• ZM1081 ZM1083 with a red contrast filter coating, for use with ZM1080
• ZM1082  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 14mmCH side-viewing, no decimal point, probe electrode
• ZM1083  + - ~  Neon-filled digital indicator tube, 14mmCH side-viewing, for use with ZM1082
• ZM1100  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 15.5mmCH top-viewing
• ZM1120 ZM1122 with a red contrast filter coating
• ZM1122  0 1 2 3 4 5 6 7 8 9  Miniature neon-filled digital indicator tube, 7.8mmCH top-viewing
• ZM1130 ZM1132 with a red contrast filter coating
• ZM1131 ZM1133 with a red contrast filter coating, for use with ZM1080
• ZM1132  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, side-viewing, left and right decimal point
• ZM1133  + - ~  Neon-filled digital indicator tube, side-viewing, for use with ZM1132
• ZM1136L/R ZM1138L/R with a red contrast filter coating
• ZM1137 ZM1139 with a red contrast filter coating, for use with ZM1136L/R
• ZM1138L/R  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 13mmCH side-viewing, left or right decimal points (specify)
• ZM1139  + - ~ Ω  Neon-filled digital indicator tube, 13mmCH side-viewing, for use with ZM1138 in digital multimeters
• ZM1162  0 1 2 3 4 5 6 7 8 9  Long-life neon-filled digital indicator tube, 15.5mmCH top-viewing, no decimal point, rectangular envelope for close stacking in both axes
• ZM1170 ZM1172 with a red contrast filter coating
• ZM1172  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 15.5mmCH side-viewing, no decimal point
• ZM1174 ZM1175 with a red contrast filter coating
• ZM1175  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 15.5mmCH side-viewing, left decimal point
• ZM1176 ZM1177 with a red contrast filter coating
• ZM1177 ZM1175, but right decimal point
• ZM1180 ZM1182 with a red contrast filter coating
• ZM1181 ZM1183 with a red contrast filter coating, for use with ZM1180
• ZM1182  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 16mmCH top-viewing, no decimal point, semi-rectangular envelope for close horizontal stacking
• ZM1183  + - ~ Ω  Neon-filled digital indicator tube, top-viewing, 13mmCH for use with ZM1182 in digital multimeters
• ZM1184D ZM1185D with a red contrast filter coating
• ZM1185A (GR1420)  1 2 3 4 5 6 U K E R  Neon-filled digital indicator tube, 16mmCH top-viewing
• ZM1185D (GR1430)  ∇ Δ  Neon-filled digital indicator tube, 16mmCH top-viewing, for use in elevators
• ZM1185E (GR1472)  0 1 2 3 4 5 - t kg +  Neon-filled digital indicator tube, 16mmCH top-viewing
• ZM1200 Pandicon, multiplexed 14-digit display tube with decimal points and punctuation marks, pin connections on both ends
• ZM1202 12-Digit Pandicon
• ZM1204 10-Digit Pandicon
• ZM1206 8-Digit Pandicon

ZM1212

• ZM1210 ZM1212 with a red contrast filter coating
• ZM1212  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 15.5mmCH side-viewing, left decimal point, all-glass pigtailed
• ZM1220 ZM1222 with a red contrast filter coating
• ZM1222  0 1 2 3 4 5 6 7 8 9  Large neon-filled digital indicator tube, 40mmCH side-viewing
• ZM1230 ZM1232 with a red contrast filter coating
• ZM1232  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 15.5mmCH upside-down side-viewing, no decimal point
• ZM1240 ZM1242 with a red contrast filter coating
• ZM1241 ZM1243 with a red contrast filter coating, for use with ZM1240
• ZM1242  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 16mmCH side-viewing, right decimal point
• ZM1243  + - ~ Ω  Neon-filled digital indicator tube, 16mmCH side-viewing, for use with ZM1242 in digital multimeters
• ZM1263  ~ ⚫  Neon-filled digital indicator tube, 10mmCH side-viewing
• ZM1290 ZM1292 with a red contrast filter coating
• ZM1292  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 10mmCH side-viewing
• ZM1330 ZM1332 with a red contrast filter coating
• ZM1331 ZM1333 with a red contrast filter coating, for use with ZM1330
• ZM1332  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 13.1mmCH side-viewing, left and right decimal points, all-glass pigtailed
• ZM1333  + - ~ Ω  Neon-filled digital indicator tube, 13.1mmCH side-viewing, all-glass pigtailed, for use with ZM1332 in digital multimeters
• ZM1334 ZM1336 with a red contrast filter coating
• ZM1335 ZM1337 with a red contrast filter coating, for use with ZM1334
• ZM1336  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 13.1mmCH side-viewing, left and right decimal points, multiplex-capable
• ZM1337  + - ~ Ω  Neon-filled digital indicator tube, 13.0mmCH side-viewing, right decimal point (!), all-glass pigtailed, red contrast filter coating, for use with ZM1336 in digital multimeters
• ZM1350 Varisymbol, planar neon-filled digital 40mm x 27mm fourteen-segment display tube, right decimal point, separate underscore text cursor, keep-alive cathode, multiplex-capable, viewing angle 160°
• ZM1360 ZM1350 with 60mm x 40mm characters
• ZM1370 ZM1350 with 20mm x 13mm characters
• ZM1410 ZM1412 with a red contrast filter coating
• ZM1412 Neon-filled digital seven-segment display tube, 8.6mmCH side-viewing, right decimal point and left punctuation mark, all-glass pigtailed
• ZM1500 Pandicon, multiplexed 12-digit, 7-segment display tube
• ZM1550 Planar neon-filled digital two-digit seven-segment display tube, right decimal points
• ZM1551 Planar neon-filled digital 1½-digit seven-segment display tube with  +  and  -  signs, right decimal points

Note: More Nixie tubes under standard - ZM and other letter - GR

ZP

• ZP1000 - Borium tri-fluoride-filled Geiger-Müller tube, thermal neutrons
• ZP1010 - Borium tri-fluoride-filled Geiger-Müller tube, thermal neutrons
• ZP1020 - Borium tri-fluoride-filled Geiger-Müller tube, thermal neutrons
• ZP1070 - Subminiature Geiger-Müller tube, all-glass pigtailed
• ZP1080 - Halogen-quenched Geiger-Müller tube, β and γ
• ZP1100 - Halogen-quenched Geiger-Müller tube, γ; pigtailed
• ZP1200 - Halogen-quenched Geiger-Müller tube, γ
• ZP1300 - Halogen-quenched Geiger-Müller tube, γ and high-energy β
• ZP1330 - Halogen-quenched Geiger-Müller tube, for use in damp and/or saline atmosphere, β and γ
• ZP1400 - Halogen-quenched Geiger-Müller tube, 9mm diameter mica window, β and γ
• ZP1430 - Halogen-quenched Geiger-Müller tube, 27.8mm diameter mica window, α, β, γ
• ZP1490 - Halogen-quenched Geiger-Müller tube, 28mm diameter mica window, low-level α, β and γ
• ZP1600 - Halogen-quenched Geiger-Müller tube, 19.8 mm diameter mica window, X-rays, 6.0 to 20 keV energy, 60 to 200 pm wavelength range
• ZP1610 - Side window, organically quenched Geiger-Müller tube. 7 x 18 mm mica window; X-rays, 2.5 to 40 keV energy, 30 to 500 pm wavelength range
• ZP1700 - Halogen-quenched, cosmic-ray guard counter tube for low-background measurements; to be used with another radiation counter tube in an anticoincidence circuit
• ZP1800 - Halogen-quenched Geiger-Müller tube for use at temperatures up to 200 °C, γ
• ZP1810 - Halogen-quenched Geiger-Müller tube for use at temperatures up to 200 °C, γ, low sensitivity, up to 40 mGy/h
• ZP1860 - Halogen-quenched Geiger-Müller tube, β and γ

ZT

• ZT1000 21 kV, 10 A Mercury vapor triode thyratron

ZX

• ZX1000 800 V, 1140 A_pk, 13A_avg Ignitron
• ZX1051 Water-cooled, 56 A_avg Ignitron
• ZX1052 Water-cooled, 140 A_avg Ignitron
• ZX1053 Water-cooled, 355 A_avg Ignitron
• ZX1060 Water-cooled, 10 A_avg Ignitron
• ZX1061 Water-cooled, 10 A_avg Ignitron
• ZX1062 Water-cooled, 10 A_avg Ignitron
• ZX1063 Water-cooled, 10 A_avg Ignitron

ZY

• ZY1000 (872B) High voltage, half-wave mercury-vapor rectifier
• ZY1001/8008A High voltage, half-wave mercury-vapor rectifier, 4-pin base with anode top cap
• ZY1002 High voltage, half-wave mercury-vapor rectifier, E40 (Goliath) Edison screw lamp base with anode top cap

ZZ

• ZZ1000 81 V Voltage reference, 2-pin all-glass pigtailed
• ZZ1010 85 V Voltage reference
• ZZ1020 (STV85-8) 82 V Voltage reference with primer electrode, 3-pin all-glass pigtailed
• ZZ1030 (STV500-0,1) Quad 125 V Voltage references, noval base
• ZZ1031 Quad Voltage reference, noval base
• ZZ1040 (STV100-60Z) 100 V Voltage reference with primer electrode
• ZZ1050 82 V Voltage reference, 2-pin all-glass pigtailed

List of European transmitting tubes

Note: Typecode explained above.

B - Backward-wave amplifier

BA

• BA9/20 X-band, 20 mW, Forced-air cooled backward wave oscillator

D - Rectifier incl. grid-controlled

DA

• DA1.5/75 1.5 kV, 75 W Half-wave power rectifier, triode TA1.5/75 without grid
• DA12/24000 24 kV, 12 kW Water-cooled half-wave power rectifier

DC

• DC1/50 1 kV, 50 mA Full-wave power rectifier, DC1/60 with dual anode top cap
• DC1/60 1 kV, 60 mA Full-wave power rectifier
• DC2/200 2 kV, 200 mA Full-wave power rectifier with dual anode top cap

DCG

• DCG1/125 1 kV, 125 mA Half-wave mercury-vapor rectifier with Edison screw lamp base and anode top cap
• DCG12/30 12 kV, 30 A Grid-controlled, half-wave mercury-vapor rectifier with anode top cap

DCX

• DCX4/1000 4 kV, 1 kW Half-wave xenon rectifier with anode top cap
• DCX4/5000 4 kV, 5 kW Half-wave xenon rectifier with anode top cap

DE

• DE2/200 2 kV, 200 W Full-wave power rectifier with dual anode top cap

J - Magnetron

JP

• JP8/02B 8.8 GHz, 25 W Magnetron
• JP9/15 9.345 to 9.405 GHz, 15 kW Forced-air cooled magnetron for pulsed service

JPT

• JPT9/01 9.15 to 9.60 GHz, 5 W Magnetron

K - Klystron

KB

• KB9/150W X-band, 150 W Water-cooled, dual-resonator klystron

L - Traveling-wave tube

LA

• LA9/3 7 to 11.5 GHz Forward-wave amplifier
• LA16/2 11.5 to 18  GHz Forward-wave amplifier

M - AF modulator Triode

MA

• MA4/600 4 kV, 600 W Radiation-cooled triode

MB

• MB1/50 1 kV, 50 W Radiation-cooled triode
• MB2/200 2 kV, 200 W Radiation-cooled triode

MY

• MY3/275 3 kV, 275 W Radiation-cooled triode

MZ

• MZ2/200 2 kV, 200 W Radiation-cooled triode

P - Pentode

PA

• PA12/15 15 kW Water-cooled shortwave pentode
• PA12/20 20 kW Water-cooled pentode made by Philips and used in the 1930s and 1940s

PAL

• PAL12/15 Air-cooled version of PAW12/15

PAW

• PAW12/15 15 kW Water-cooled shortwave pentode

PB

• PB2/200 200 W Shortwave pentode
• PB3/1000 1 kW Shortwave pentode

PC

• PC03/3 3 W Shortwave pentode
• PC3/1000 1 kW Shortwave pentode

PE

• PE04/10 10 W Shortwave pentode
• PE1/100 (YL1200) 100 W Shortwave pentode

Q - Tetrode

QB

• QB2/75 75 W Beam-tetrode
• QB5/2000 2 kW Beam-tetrode

QBL

• QBL4/800 Air-cooled 800 W beam-tetrode
• QBL5/3500 Air-cooled 3500 W beam-tetrode

QBW

• QBW5/3500 Water-cooled 3500 W beam-tetrode

QC

• QC05/15 15 W Beam-tetrode
• QC05/35 35 kW Beam-tetrode

QE

• QE04/10 10 W Beam-tetrode
• QE05/40 (6146) 40 W Radiation-cooled output beam-tetrode, popular amongst radio amateurs as a final RF amplifier
• QE08/200 200 W Beam-tetrode

QEL

• QEL1/150 Air-cooled 150 W beam-tetrode
• QEL1/250 Air-cooled 250 W beam-tetrode

QEP

• QEP20/18 18 W Beam-tetrode for use as a pulse modulator

QQC

• QQC03/14 14 W Dual beam-tetrode

QQE

• QQE02/5 (6939) 5 W Dual beam-tetrode
• QQE03/12 (6360) 12 W Dual beam-tetrode
• QQE03/20 (6252) 20 W Dual beam-tetrode
• QQE04/5 (7377) 5 W Dual beam-tetrode
• QQE06/40 (5894, YL1060) 40 W dual beam-tetrode, internally neutralized, Septar base with dual anode top cap

QQV

• QQV02/6 6 W dual beam-tetrode
• QQV03/20A 20 W Radiation-cooled split-anode tetrode made by Mullard and used in the 1940s, 1950s and 1960s as a VHF frequency-doubling output stage with balanced output.
• QQV07/50 50 W Dual beam-tetrode

QQZ

• QQZ03/20 (8118, YL1020) 20 W Dual beam-tetrode
• QQZ06/40 (YL1030) 40 W Dual beam-tetrode

QV

• QV04/7 7 W Beam-tetrode
• QV05/25 (807) 25 W Radiation-cooled output beam-tetrode made by Mullard.
• QV2/250C 250 W Beam-tetrode

QY

• QY3/65 65 W Beam-tetrode
• QY5/3000A 3 kW Beam-tetrode
• QY5/3000W Water-cooled version of QY5-3000A

QYS

• QYS50/P40 Pulsed power tetrode, Silica envelope, 50 kV anode voltage, considerable x-radiation, 810 °C anode temperature at 700 W anode dissipation, 40 A anode current at duty factor 0.0005, U_g1Cut-off (I_A=1 mA@U_A=55 kV): > -3.4 kV, g_m: 38 mS

QZ

• QZ06/20 25 W VHF Power tetrode up to 175 MHz

R - Rectifier

RG

• RG1000/3000 1 kV, 3 A Half-wave mercury-vapor rectifier with anode top cap

RGQ

• RGQ7.5/0.6 7.5 kV, 600 mA Half-wave mercury-vapor rectifier with anode top cap
• RGQ20/5 20 kV, 5 A Half-wave mercury-vapor rectifier with anode top cap

T - AF/RF/oscillator Triode

TA

• TA04/5 400 V, 50 W Radiation-cooled power triode
• TA1.5/75 1.5 kV, 75 W Radiation-cooled power triode
• TA4/2000K 4 kV, 2 kW Air-cooled power triode made by Philips in the 1930s
• TA18/100000 18 kV, 100 kW Water-cooled power triode

TB

• TB2.5/400 2.5 kV, 300 W Radiation-cooled power triode
• TB5/2500 5 kV, 2.5 kW Radiation-cooled power triode

TBL

• TBL2/300 2 kV, 300 W Forced air-cooled power triode
• TBL15/125 15 kV, 125 kW Forced air-cooled power triode

TBW

• TBW6/14 6 kV, 14 kW Water-cooled power triode
• TBW15/125 15 kV, 125 kW Water-cooled power triode

TX

• TX12/12W Water-cooled RF power triode
• TX12/20W Water-cooled RF power triode
• TX10/4000 Power triode, Silica envelope, 12 kV anode voltage, 4 kW anode dissipation, 1.6 A cathode current, g_m: 4.5 mS, for use as self-excited high-power oscillator in induction heating equipment.

TY

• TY2/125 135 W VHF power triode up to 200 MHz
• TY12/50A Forced-air cooled 45 kW RF power triode up to 30 MHz
• TY12/50W Water-cooled 50 kW RF power triode up to 30 MHz

TYS

• TYS2/250 Power triode, Silica envelope, 2.5 kV anode voltage, 250 W anode dissipation
• TYS4/500 Power triode, Silica envelope
• TYS5/1000 Power triode, Silica envelope
• TYS5/2000 Power triode, Silica envelope
• TYS5/3000 Power triode, Silica envelope, 6 kV anode voltage, 950 °C anode temperature at 3.5 kW anode dissipation, 2.8 A cathode current, g_m: 15 mS. Used in RF generators for induction hardening.

X - Thyratron

XGQ

• XGQ2/6400 2 kV, 6.4 kW Mercury-vapor tetrode thyratron with anode and grid1 top caps

XR

• XR1/1600 (5545) 1 kV, 1.6 kW Inert gas-filled triode thyratron with anode top cap
• XR1/6400 1 kV, 6.4 kW Inert gas-filled triode thyratron with anode top cap

List of other letter tubes

A

AC/

Mazda/Ediswan 4 volts AC, indirectly heated receiver tubes:

• AC/HL AF triode, British 5-pin base
• AC/HLDD Dual diode and AF triode, British 7-pin base
• AC/ME Tuning indicator, British 7-pin base
• AC/P, AC/P1 AF triode, British 5-pin base
• AC/P4 CRT electrostatic-deflection output power triode, British 5-pin base
• AC/PEN AF power pentode, British 7-pin base
• AC/S2PEN RF pentode, British 7-pin base
• AC/SP1 RF pentode for use in squelch circuits or, as the reactance tube, in AFC circuits, British 7-pin base
• AC/SP3 RF pentode for shortwave and TV receivers, British 7-pin base
• AC/SP3/RH Low-noise, low-microphonics RF pentode for shortwave and TV receivers, British 7-pin base
• AC/TH1 Triode/hexode oscillator/mixer, British 9-pin base
• AC/TP Triode/pentode oscillator/mixer, British 7-pin base
• AC/VP1, AC/VP2 RF pentode, British 7-pin base
• AC2/HL High-mu triode
• AC2/PEN AF Power pentode
• AC2/PEN.DD Dual diode and AF Power pentode
• AC4/PEN AF Beam power pentode
• AC5/PEN AF Beam power pentode
• AC5/PEN.DD Dual diode and AF Beam power pentode
• AC6/PEN Beam power pentode for use as a magnetic horizontal-deflection output amplifier

ACT

Marconi-Osram:

• ACT9 800 W Air cooled transmitting triode up to 15 MHz, with derating up to 80 MHz

AT

Mullard:

• AT4 Acorn UHF triode up to 430 MHz

B

BA

Industrial Electronics Engineers:

• BA-0000-P31 Nimo tube, cathode-ray 1-digit numeric display tube, 10 stenciled electron guns aiming at a P31-phosphor (green, medium-persistence) fluorescent screen, top-viewing, Futura Medium font, 2.5 kV anode voltage, 12-pin base

BG

Burroughs:

• BG08220-K Neon-filled, planar, base-24 display dekatron with four sets of guiding cathodes and a carry/borrow cathode, for use e.g. in direction-finding equipment

C

CH

Tung-Sol:

• CH1027 Curristor - Four types of nitrogen-filled, radioactive constant-current tubes with a current plateau from 25 to 500 V, all-glass pigtailed, active material is ²²⁶Ra with a half-life of 1601 years, for linear capacitor charging and draining in missile and ordnance mine timing circuits, instrumentation biasing, as current reference, etc.:
  • CH1027-9 10⁻⁹ A, 18.75 μCi
  • CH1027-10 10⁻¹⁰ A, 1.875 μCi
  • CH1027-11 10⁻¹¹ A, 187.5 nCi
  • CH1027-12 10⁻¹² A, 18.75 nCi

CL

Ferranti:

• CL40 and CL41 Indirectly heated, linear light source (glow modulator tube), mercury/argon-filled gas diode with primer electrode, 8-pin base, for rotating-drum FAX receivers, film soundtrack recording, etc.
• CL42 and CL43 Indirectly heated, low-noise linear light source, helium-filled gas diode with primer electrode, 8-pin base, for film soundtrack recording, interferometers, etc.
• CL55 Indirectly heated, spectrally pure light source, helium-filled gas diode with primer electrode, 7-pin base with anode top cap
• CL56 Indirectly heated, spectrally pure light source, krypton-filled gas diode with primer electrode, 7-pin base with anode top cap
• CL57 Indirectly heated, spectrally pure light source, neon-filled gas diode with primer electrode, 7-pin base with anode top cap
• CL58 Indirectly heated, spectrally pure light source, xenon-filled gas diode with primer electrode, 7-pin base with anode top cap
• CL60 Indirectly heated triode CRT-type stroboscope lamp with a green A-type phosphor with <1 μs decay time and 10 kCd light output, 20 kV anode voltage, 7-pin duodecal base
• CL61 CL60 with a blue P-type phosphor with 5 μs decay time and 16 kCd light output
• CL62 CL60 with an UV Q-type phosphor with 100 ns decay time and 240 Cd light output
• CL63 CL60 with a yellow-green C-type phosphor with 6 μs decay time and 24 kCd light output
• CL64 CL60 with a yellow V-type phosphor with 5 μs decay time and 12 kCd light output
• CL65 CL60 with a red R-type phosphor with 2 μs decay time and 14 kCd light output
• CL66 CL60 with a white T-type phosphor with 5 μs decay time and 12 kCd light output

D

Philips:

• D1 Early directly heated triode used in 1920s TRF and regenerative radios

DDR

Mullard:

• DDR100 100 g max., 250 Hz max., 1-axis accelerometer double diode with elastically supported anodes, 6.3V/600mA indirect heater, f_res = 1 kHz, B8G base

DZ

Cerberus:

• DZ10 3 kHz max. Decade Counter/Selector Dekatron, 14-pin diheptal base

E

EN

Ferranti:

• EN10 Neostron, 400 A_pk Gas-filled, cold-cathode tetrode thyratron, differential trigger electrodes, 8-pin base, for use as a relay or as a reddish 700 Cd stroboscope lamp
• EN15 80 A_avg Neon-filled, cold-cathode tetrode thyratron, differential trigger electrodes, miniature 9-pin base, for use as a stroboscope lamp
• EN30 250 A_pk Gas-filled, arc-discharge cold-cathode tetrode thyratron, differential trigger electrodes, miniature 7-pin base with anode cap, for use as a relay or as a stroboscope lamp
• EN40 250 A_pk Gas-filled, cold-cathode tetrode thyratron, differential trigger electrodes, 8-pin base, for use as a whitish stroboscope lamp with a high actinism for photographic film
• EN55 Xenon-filled, arc-discharge cold-cathode tetrode thyratron, external (capacitive) trigger, 12-pin base, for use as a white 140 kCd stroboscope lamp
• EN60 Gas-filled, arc-discharge cold-cathode tetrode thyratron, external (capacitive) trigger, Edison screw lamp base with anode cap, for use as a white 900 klm@10µF@800V stroboscope lamp

EST

• EST15 Power pentode, B9 base - Ruggedized version of PL84

G

Standard Telephones and Cables/Brimar:

• G10/241E Nomotron, an unidirectional Dekatron with multi-alloy cathodes

Cerberus:

• G11 5 mA Gas-filled, cold-cathode switching diode e.g. for relaxation oscillators, 2-pin all-glass pigtailed
• G42 35 mA_peak Gas-filled switching diode e.g. for relaxation oscillators, 2-pin all-glass pigtailed

GC

Ericsson Telephones Limited:

• GC10/2P Neon-filled, 1 kHz Miniature decade Counter Dekatron, a gas-filled, bidirecional decade counter tube
• GC10A Helium-filled, decade Counter Dekatron
• GC10B Neon-filled, 4 kHz Long life, decade Counter Dekatron
  • GC10/4B 4 kHz Decade Computing Counter Dekatron with carry/borrow cathodes "0" and "9" and intermediate cathodes "3" and "5" wired to separate pins
• GC10D 20 kHz Decade Counter Dekatron, for single-pulse operation
• GC12/4B 4 kHz Duodecimal Counter Dekatron with carry/borrow cathodes 11 and 12 and intermediate cathodes 6 and 8 wired to separate pins

GCA

Ericsson Telephones Limited:

• GCA10G 10 kHz max. Decade Counter Dekatron with routing guides and aux anodes to directly drive Nixie tubes, B27A base without the inner pin ring

GD

Ericsson Telephones Limited:

• GD2V 2 kV, 16 J discharge tube, all-glass studded
• GD75P 75 V Voltage reference, miniature 7-pin base
• GD90M 90 V Voltage reference, miniature 7-pin base
• GD350X 350 V Corona voltage reference, all-glass pigtailed
• GD550W 550 V, 1.5 J Discharge tube, e.g. for power relaxation oscillators, all-glass pigtailed

GDT

Ericsson Telephones Limited:

• GDT120M 9 mA Gas-filled cold-cathode DC triode, one starter and a separate glow diode acting as an optical primer, miniature 7-pin base

GE

Ferranti:

• GE10 Directly heated saturated-emission diode. Acts as a heating current-controlled, variable series resistor in voltage/current stabilizer circuits. It has two shorted pins that can be used to disable the circuit if the tube is removed from its socket

GK

Cerberus:

• GK11 Illuminated capacitance touch switch - cold-cathode DC relay tube, external (capacitive) starter activated by touching; then the cathode glow is visible as an orange ring. 2-pin all-glass pigtailed

GN

Ferranti:

• GN10 250 Amps pulse-current, cold-cathode tetrode thyratron. Octal base

GR

Ericsson Telephones Limited:

• GR2G  + -  Neon-filled digital indicator tube, 18 x 18 mm characters, side-viewing
• GR2H  + -  Neon-filled digital indicator tube, 20 x 20 mm characters, top-viewing
• GR4G  ¼ ½ ¾ 1  Neon-filled digital indicator tube, 18 x 30 mm characters, side-viewing
• GR7M  + - V A Ω % ~  Neon-filled digital indicator tube, 15.5 mm character height, top-viewing
• GR10A Gas-filled digital indicator tube with a dekatron-type readout
• GR10G  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 16.86 x 30 mm characters, side-viewing
• GR10H  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 12 x 19 mm characters, top-viewing
• GR10J  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 16.86 x 30 mm characters, side-viewing
• GR10K  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 12 x 19 mm characters, top-viewing
• GR10M  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 10 x 15.5 mm characters, top-viewing
• GR10W  0 1 2 3 4 5 6 7 8 9  Neon-filled digital indicator tube, 8.42 x 15 mm characters, side-viewing, all-glass pigtailed
• GR12G  A B C D E F G H I J K L  Neon-filled digital indicator tube, 16 x 30 mm characters, side-viewing
• GR12H  E L M N P R S T U V W X  Neon-filled digital indicator tube, 16 x 30 mm characters, side-viewing

Note: More Nixie tubes under standard - ZM and professional - ZM

Cerberus:

• GR15 15 mA Gas-filled cold-cathode DC tetrode, one starter and one electrical primer and tritium-primed (half-life: 12.32 years), noval base, for voltage triggers, RC timers etc.
• GR16 20 mA Gas-filled, cold-cathode, tritium-primed AC/DC triode, one starter and an EM shield, noval base, for voltage triggers, RC timers etc.
• GR17 15 mA Gas-filled cold-cathode AC triode, one starter and an EM shield, noval base, for voltage triggers, RC timers etc.
• GR31 15 mA Gas-filled cold-cathode DC tetrode, one starter and one electrical primer plus a tritium primer, noval base
• GR44 12 mA Subminiature gas-filled cold-cathode DC pentode, two starters and one primer electrode plus a tritium primer, 5-pin all-glass pigtailed
• GR46 12 mA Subminiature gas-filled cold-cathode DC tetrode, one starter and one primer electrode, 4-pin all-glass pigtailed

GRD

Ferranti:

• GRD7 Educational, directly heated saturated-emission guard ring diode

GS

Ericsson Telephones Limited:

• GS10C 4 kHz max. Decade Counter/Selector Dekatron, top-viewing, duodecal base
• GS10D Hydrogen-filled, 20 kHz max. Decade Counter/Selector Dekatron, duodecal base
• GS10H 4 kHz max. Decade Counter/Selector Dekatron with routing guides, B17A base
• GS12C 4 kHz max. Duodecimal Counter/Selector Dekatron, with solder lugs
• GS12D Neon-filled, 4 kHz max. duodecimal Counter/Selector Dekatron, duodecal base with two additional pigtails for the guide electrodes

GSA

Ericsson Telephones Limited:

• GSA10G 10 kHz max. Decade Counter/Selector Dekatron with routing guides and aux anodes to directly drive Nixie tubes, B27A base

GTE

Ericsson Telephones Limited:

• GTE120Y 5 mA Subminiature DC trigger tetrode, one starter and one primer, all-glass pigtailed
• GTE130T 8 mA_peak DC trigger tetrode, one starter and one primer, close tolerance, low aging, quadrant I operation only, noval base
• GTE175M 3.5 mA_avg, 50 mA_peak DC Trigger tetrode, one starter and one primer, miniature 7-pin base, for Dekatron coupling circuits

GTR

Ericsson Telephones Limited:

• GTR120W 9 mA Subminiature DC trigger triode, 3-pin all-glass pigtailed, for computer applications
• GTR75M 75 V Voltage reference, Miniature 7-pin
• GTR95M/S 95 V Voltage reference, Miniature 7-pin
• GTR150 Subminiature, primed 150 V voltage reference, all-glass pigtailed

H

HD

• HD94/6BQ6GTA/6BQ6GTB/6CU6: TV horizontal output beam power pentode. Octal with anode at top cap
• HD96/25BQ6GTB/25CU6: TV horizontal output beam power pentode. Octal with anode at top cap

K

KN

KN2

Edgerton, Germeshausen, and Grier:

• KN2 4 kV, 500 A_surge Krytron, a cold-cathode gas-filled tube with primer electrode, for use as a very high-speed switch; similar to a thyratron, lifespan 10⁷ shots, 4-pin all-glass pigtailed
• KN4 5 kV, 2.5 kA_surge Krytron with primer electrode, lifespan 25000 shots, 4-pin all-glass pigtailed
• KN6 5 kV, 3 kA_surge Krytron with primer electrode, lifespan 35000 shots, 4-pin all-glass pigtailed
• KN6B 8 kV, 3 kA_surge Krytron with primer electrode, lifespan 35000 shots, 4-pin all-glass pigtailed
• KN9 4 kV, 500 A_surge Krytron with primer electrode, lifespan 1.5⋅10⁷ shots, 4-pin all-glass pigtailed
• KN22 5 kV, 100 A_surge Krytron with primer electrode, lifespan 2⋅10⁷ shots, 4-pin all-glass pigtailed, for laser pumping, to drive Pockels cells, also for educational purposes
• KN26 5 kV, 3 kA_surge Krytron with primer electrode, lifespan 75000 shots, 4-pin all-glass pigtailed

KT

Marconi-Osram Kinkless Tetrode beam power tubes

• KT32 (25L6, 25L6G, 25L6GT and 25W6GT)
• KT33 (25A6GT)
• KT41
• KT61 (6M6G) in parallel filament circuits
• KT63 (6F6, 6F6G, 6F6GT)
• KT66 (6L6GC)
• KT67 small transmitting valve
• KT71 (50L6GT)
• KT77 Similar to EL34, 6CA7
• KT81
• KT88 = 6550A = CV5220 (12E13, 7D11) AF beam power tube, two tubes are capable of providing 100W output, Class-AB₁, octal base.
• KT90

Tung-Sol:

• KT120 New production tube
• KT150 New production tube

M

M8000s

Mullard:

• M8083 = EF91 = 6AM6 = Z77 Sharp-cutoff pentode, miniature 7-pin base
• M8162 = ECC81 = 12AT7 = 6060 = B309 High-mu dual triode, for use as RF amplifier/mixer in VHF circuits, noval base

ME

Mazda:

• ME91 AC/DC mains tuning indicator

P

PBG

Dale:

• PBG12201 Neon-filled, planar, dual 200-segment linear glow-transfer bar graph display tube with three cathode strings, for use in VU meters etc.; cf. BG08220-K
• PBG12203 Neon-filled, planar, dual 201-segment linear glow-transfer bar graph display tube with three cathode strings, for use in VU meters etc.
• PBG12205 Neon-filled, planar, dual 200-segment linear glow-transfer bar graph display tube with five cathode strings, for use in VU meters etc.
• PBG16101 Neon-filled, planar, dual 101-segment linear glow-transfer bar graph display tube with three cathode strings, for use in VU meters etc.; similar to ИН-33

PD

Mazda:

• PD220 Dual AF power triode for battery-supplied equipment (1939)

PL

Philips:

• PL21 = 2D21 = EN91 100 mA_avg, 500 mA_peak, 10 A_surge, Gas-filled, indirectly heated tetrode thyratron, negative starter voltage, miniature 7-pin base, for relay and grid-controlled rectifier service
• PL323 = 3C23 1.5 A_avg, 6 A_peak, Mercury-vapor triode thyratron, 4-pin base with anode top cap
• PL5727 = 5727 100 mA_avg, 500 mA_peak, 10 A_surge, Tetrode thyratron, 7-pin miniature base

Q

QK

Raytheon:

• QK329 Beam-deflection square-law tube for use as a function generator in analog computers. A flat sheet beam is deflected across the anode which is partially covered by a parabolically stenciled screen "grid" that acts as the tube's output. Two tubes may be combined to form a 1-quadrant analog multiplier using the equation a⋅b = (a+b)² − (a−b)²/4 where the deflection electrode signals a+b and a−b can be obtained directly from a fully balanced resistor bridge

R

• R Early directly heated triode used by many amateurs in the 1920s

S

SU

Cossor:

• SU25 EHT rectifier
• SU2150 (CV1120) High-voltage vacuum half-wave rectifier for use in CRT power supplies

SY

Standard Telephones and Cables:

• SY4307A (4307A) Power pentode similar to the output beam-tetrode type 807. It differs from an 807 by being a directly heated pentode rather than an indirectly heated beam-tetrode. Both types are contained in an ST-16 bulb with an anode cap and 5-pin "American" UY base

This device is historically notable because a pair of them in parallel Class-C was used as the output stage in a transmitter built in secret by Australian soldiers in Japanese-occupied Portuguese Timor during World-War II in 1942. This transmitter, now reconstructed and on display at the Australian War Memorial in Canberra, was called "Winnie the War Winner".

T

TT

Bendix:

• TT8 Chronotron, an integrating, balanced-bridge hot-wire/PTC ammeter

Marconi-Osram:

• TT11 Low power VHF transmitting beam tetrode
• TT21 RF power beam-tetrode derived from KT88
• TT100 RF power beam-tetrode

V

VHT

Ferranti:

• VHT1 Pentagrid converter, 1933

VS

Ericsson Telephones Limited:

• VS10G Trochotron, an electron-beam decade counter tube
• VS10G-M VS10G with a magnetic shield
• VS10H High-current trochotron
• VS10K Low-voltage trochotron

List of other number tubes

1

1600s

• 1602 Directly heated triode used for A.F.amplification with low microphonics. 7.5 volt heater/filament. 12 watts of A.F. operating in Class-A. 15 watts of low R.F. operating in Class-C. Similar to type 10.
• 1603 Indirectly heated pentode used for A.F. amplification with low microphonics. Similar to types 6U7, 57, 6D6 and 6C6. UX6 Base.
• 1608 Directly heated triode giving 20 watts at up to 45 MHz. 2.5 volt heater/filament. UX base.
• 1609 Directly heated pentode used for A.F. amplification with low microphonics. American 5-Pin(UY)base.
• 1610 Directly heated pentode specially designed for use as a crystal oscillator. 2.5 volt heater/filament, American 5-Pin base.
• 1612 Pentagrid converter; low-microphonics version of type 6L7. Both control grids (1 and 3) are sharp-cutoff.
• 1619 Beam Power Tetrode, similar to 6L6 with directly heated filament, common in WW2 battle tank transmitters.
• 1624, 1625 very similar to the 807, but with different heater voltage
• 1626 RF triode, very similar to 6J5 but with 12.6 volt filament
• 1629 Tuning indicator tube with DC amplifier triode unit
• 1630 Indirectly heated, orbital-beam, secondary-emission, 12-pin Jumbo Acorn-type UHF hexode
• 1633 Dual triode, equivalent to 6SN7 with 26 volt filament (WW2 aircraft use)
• 1635 Indirectly heated, 10.4 W dual AF power triode, 8-pin base
• 1650 High-altitude version of the 955 Acorn-type triode
• 1680 Dual-control heptode for use as a NAND gate in a coincidence circuit in IBM computers, 6BE6/EK90 with a sharp-cutoff grid no.3

2

• 24B1 Trigatron
• 24B9 Trigatron
• 29C1 Directly heated saturated-emission diode; acts as a heating current-controlled, variable series resistor in voltage/current stabilizer circuits.

200s

• 203A 40 W, Directly heated RF transmitter power triode, 4-pin base, anode on top cap
• 204A 450 W, Directly heated RF transmitter power triode, 3-pin base, anode on top cap
• 205D 1 W, Directly heated AF or modulator power triode, 4-pin base
• 207 22.5 kW, Water-cooled, directly heated RF transmitter power triode
• 210T Directly heated RF transmitter power triode, 4-pin base, similar to type 10 triode with an isolantite base
• 210DET Cossor directly heated, 2 volts, special detector
• 210HF Cossor, directly heated, 2 volts, triode
• 210HL Cossor, directly heated, 2 volts, triode
• 210LF Cossor, directly heated, 2 volts, triode
• 210PG Cossor, directly heated, 2 volts, variable-mu pentagrid
• 210RC Cossor, directly heated, 2 volts, very high impedance triode
• 210SPT Cossor, directly heated, 2 volts, HF pentode
• 210VPT Cossor, directly heated, 2 volts, HF variable-mu shielded pentode
• 211 260 W, Directly heated AF or modulator power triode now favored by audiophiles; 4-pin base
• 212E 250 W, Directly heated RF transmitter power triode, 4-pin base
• 215P Directly heated AF power triode
• 220B 5 kW, Water-cooled, directly heated AF/modulator power triode
• 228 2.5 kW, Directly heated RF/AF power triode
• 230XP Directly heated power triode
• 232C 8.5 kW, Water-cooled, directly heated RF transmitter power triode
• 236A 12 kW, Water-cooled, directly heated RF transmitter power triode
• 240B Directly heated dual AF power triode
• 241B 300 W, Directly heated AF/modulator power triode, 3-pin base, anode on top cap
• 242A Directly heated AF/modulator power triode, 4-pin base
• 250TH 1.1 kW, Directly heated AF/modulator power triode, 4-pin base, anode on top cap
• 254A 14 W, Directly heated RF transmitter power triode, 4-pin base, anode on top cap
• 261A 170 W, Directly heated AF/modulator power triode, 4-pin base
• 268A 20 W, Directly heated power triode, 4-pin base, anode on top cap
• 270A 585 W, Directly heated AF/RF power triode, 4-pin base, anode on top cap
• 275A 3 W, Directly heated AF power triode, 4-pin base
• 276A 170 W, Directly heated AF/RF power triode, 4-pin base
• 279A 1.75 kW, Directly heated AF/RF power triode
• 295A 125 W, Directly heated AF/RF power triode, 4-pin base
• 298A 5 kW, Water-cooled, directly heated power triode

3

• 300B 40 watt directly heated power triode, 4-pin base

4

• 4XP Directly heated power triode
• 41MP Indirectly heated power triode
• 45 (CX345) Directly heated power triode
• 402P Indirectly heated power triode, 7-pin base

7

• 7JP1 Monochrome cathode ray tube for use in early postwar oscilloscopes. Electrostatic deflection, P1 green, short-persistence phosphor, 7" screen.
• 7JP4 Monochrome cathode ray tube common in early postwar TV receivers. Electrostatic deflection, P4 white, medium-persistence phosphor, 7" screen.
• 7JP7 Monochrome cathode ray tube for use in early postwar radar displays. Electrostatic deflection, P7 blue-white, long-persistence phosphor, 5½" screen.

8

800s

• 800 Directly heated V.H.F. power triode, giving 35 watts up to 60 MHz and 18 watts at 180 MHz. American 4-Pin(UX)base with side locating pin.
• 801Directly heated power triode, used in pairs in Class-B in A.M. modulation sections of transmitters giving up to 45 watts of power at 60 MHz and 22 watts at 120 MHz.
• 802 Indirectly heated H.F. power pentode, giving 8 watts up to 30 MHz and 4 watts at 110 MHz.
• 803 Directly heated H.F. power pentode, giving 50 watts up to 20 MHz and 25 watts at 70 MHz.
• 804 Directly heated H.F. power pentode, giving 20 watts up to 15 MHz and 10 watts at 10 MHz.
• 805 Directly heated H.F. high-mu triode, giving 140 watts up to 30 MHz and 70 watts at 85 MHz..
• 806 Directly heated H.F. high-mu triode, giving 390 watts up to 30 MHz 195 watts at 100 MHz.
• 807 Indirectly heated H.F. beam power tetrode, giving 25 watts up to 30 MHz and 12 watts at 125 MHz. A variation of type 6L6 originally designed as a Class-C transmitter tube. Later used in pairs as push-pull outputs for high-wattage Class-AB₂ audio amplifiers. Also used as a horizontal output tube in early TV receivers. One of the first commercial tubes that used the top cap to connect the plate (instead of the control grid) to the circuit.
• 808 Directly heated H.F. high-mu triode, giving 140 watts up to 30 MHz and 70 watts at 130 MHz.
• 809 Directly heated H.F. high-mu triode, giving 55 watts up to 27 MHz and 30 watts at 100 MHz.
• 810 Directly heated H.F. triode, 10 volt filament and Zirconium Carbide anode. Base fits R.C.A. UT-541A Socket.
• 811A Directly heated H.F. triode, 6.3 volt filament, 88 watts

• 813 Beam Power Tetrode possessing about 5 times the Anode dissipation of an 807.
• 814 A directly heated Beam Power Tetrode giving about 130 watts at 30 MHz and 65 watts at 100 MHz operating in Class-C.
• 815 An indirectly heated dual Pentode. International Octal, (IO), base.
• 829 A dual indirectly heated beam power tetrode. Two 6.3 volt heaters sharing a common tap.
• 830 A directly heated triode giving about 50 watts at 15 MHz and 7.5 watts at 60 MHz operating in Class-C.
• 831 A directly heated triode giving about 400 watts at 20 MHz and 200 watts at 60 MHz operating in Class-C. 11 volt heater/filament.
• 833 A larger directly heated high-mu triode giving about 1 kW at 30 MHz and 500 watts at 45 MHz operating in Class-C. Usable up to 100 MHz at reduced power, (400 W). 10 volt heater/filament drawing 10 A. The anode/Plate of this device is fabricated from tantalum. Plate current of 800 mA with a plate voltage of 3 kV and grid voltage of zero. Plate current of 4.3 A at a voltage of 750 with 350 volt on the grid. Superseded by the 833A. Uses two-part R.C.A socket assembly UT-103.
• 833A A larger directly heated high-mu triode giving about 1 kW at 30 MHz and 500 watts at 45 MHz and 400 watts at 100 MHz operating in Class-C. 10 volt heater/filament drawing 10 A. The anode/Plate of this device is fabricated from tantalum.
• 834 A directly heated triode giving 58 watts at 100 MHz and 25 watts at 350 MHz operating in Class-C. 7.5 volt heater/filament. Fitted with an American 4-Pin, (UX4), base with side locating pin.

• 836 An indirectly heated high vacuum rectifier with a peak inverse voltage of 5 kV and peak anode current of 1 ampere. 2.5 volt heater.
• 837 An indirectly heated pentode giving 11 watts at 20 MHz and 5 watts at 80 MHz. operating in Class-C. 12.6 volt heater.
• 838 A directly heated triode giving about 100 watts at 30 MHz operating in Class-C. 10 volt heater/filament.

• 841 A directly heated high-mu triode giving about 10 watts at 6 MHz and 5 watts at 170 MHz operating in Class-C. 7.5 volt heater/filament.
• 842 A directly heated triode giving about 3 watts at 6 MHz operating in Class-C. 7.5 volt heater/filament.
• 843 An indirectly heated tetrode giving gain at 6 MHz and usable up to 200 MHz operating in Class-C. 2.5 volt heater/filament.
• 844 A directly heated triode giving gain at 6 MHz and usable up to 155 MHz operating in Class-C. 2.5 volt heater/filament.
• 845 A directly heated triode giving up to 24 watts if undistorted power in Class-A at audio frequency with an anode voltage of 1250. 11 volt heater/filament.

• 849 A directly heated triode giving gain at 3 MHz operating in Class-C. Two 849s, working in push-pull Class-B are capable of delivering 1.1 kW of audio output with an anode voltage of 3 kV. Usable up to 30 MHz. 11 volt filament/heater.
• 850 A directly heated tetrode giving 120 watts of power gain up to 13 MHz and 50 watts at 100 MHz, operating in Class-C. 10 volt heater/filament.
• 851 A directly heated triode giving 1.5 kW of power up to 3 MHz operating in Class-C. 11 volt heater/filament.
• 852 A directly heated triode giving 75 W of power up to 30 MHz operating in Class-C. 10 volt heater/filament.
• 857B Large mercury-vapor rectifier used in 50 kW class broadcast transmitters. 22 kV anode voltage, 10 A anode current. Filament 5 V @ 30 A

• 860 A directly heated tetrode giving 105 W of power up to 30 MHz and 50 watts at 120 MHz operating in Class-C. 10 volt heater/filament.
• 861 A directly heated triode giving 400 W of power up to 20 MHz and 200 watts at 60 MHz operating in Class-C. 11 volt heater/filament.
• 862 Large water-cooled triode for broadcast/industrial applications. Used in experimental 500 kW transmitter at WLW.

• 864 A directly heated general-purpose, low-microphonics triode with a maximum anode voltage of 135 and anode current of 3.5 mA. 1.1 volt heater/filament.
• 865 A directly heated tetrode giving 30 W of power up to 15 MHz 15 watts at 70 MHz operating in Class-C. 11 volt heater/filament.

866A

• 866 A mercury-vapor rectifier with a peak inverse voltage of 5 kV and peak anode current of 1 ampere. Average anode current, 250 mA, forward drop, 15 volt. Heater voltage and current, 2.5 at 5 A. American 4-Pin(UX) base. Superseded by 866A
• 866A A mercury-vapor rectifier with a peak inverse voltage of 10 kV and peak anode current of 1 ampere. Average anode current, 250 mA, forward drop, 10 volt. Heater voltage and current, 2.5 at 5 A. American 4-Pin (UX) base.
• 872 A mercury-vapor rectifier with a peak inverse voltage of 5 kV and peak anode current of 5 amperes. Average anode current, 1250 mA, forward drop, 15 volt. Heater voltage, 5.0 at 10 A. Base fits R.C.A. UT-541A Socket.
• 872A A mercury-vapor rectifier with a peak inverse voltage of 10 kV and peak anode current of 5 amperes. Average anode current, 1250 mA, forward drop, 10 volt. Heater voltage, 5.0 at 6.25 A. Base fits R.C.A. UT-541A Socket.
• 879 A high vacuum rectifier with a peak inverse voltage of ca. 15 kV and peak anode current of ca. 5 mA. 2.5 volt heater and American 4-Pin, (UX) base. Used as half wave rectifier for high voltage cathode ray tube supplies. Similar to type 2X2.
• 884 An indirectly heated triode thyratron. 6.3 volt heater/filament, International Octal, (IO), base. Electrically similar to type 885. Once commonly used as a sawtooth horizontal sweep waveform generator in recurrent-sweep oscilloscopes. Marketed by DuMont under the type number 6Q5.
• 885 An indirectly heated triode thyratron. 2.5 volt heater/filament, American 5-Pin (UY) base. Otherwise similar to type 884.
• 898 Large water-cooled triode for broadcast/industrial applications. Updated version of 862, with 3 phase filament structure.

9

900s

• 934 Vacuum Phototube, spectral S4 response (maximum sensitivity at 400±50 nm), 3-pin Small-Shell Peewee base
• 935 Vacuum Phototube, spectral S5 response (maximum sensitivity at 340±50 nm), 4-pin octal base
• 950 Power pentode with directly heated cathode, used in storage battery home radios with 2.0 volt filament supply. Similar to types 1F4 and 1J5G
• 951 Sharp-cutoff pentode with directly heated cathode, used in storage battery home radios with 2.0 volt filament supply. Similar to type 1B4P
• 953 Acorn-type UHF diode; 6.3 V heater
• 954 (4672/E1F) Indirectly heated Acorn-type sharp-cutoff pentode giving gains of 2-3 up to 300 MHz operating in Class-A and usable up to 600 MHz with careful stage design; 6.3 V heater
• 955 (4671/E1C) Indirectly heated Acorn-type triode giving a power of 135 mW up to 600 MHz operating in Class-A and 500 mW in Class-C with careful stage design; 6.3 V heater
• 956 (4695/E2F) Indirectly heated Acorn-type remote-cutoff pentode giving gains of 3-4 up to 600 MHz operating in Class-A with careful stage design; 6.3 V heater
• 957 (D1C) Directly heated Acorn-type UHF receiving triode; 1.25 V filament for portable equipment
• 958 (D2C) Directly heated Acorn-type UHF transmitting triode with dual, paralleled 1.25 V filaments for increased emission, for portable equipment
• 959 (D3F) Directly heated Acorn-type sharp-cutoff UHF pentode; 1.25 V filament for portable equipment
• 991 60-Volts Voltage reference, T4½ lightbulb with dual-contact, bayonet candelabra mount

9000s

• 9001 954 with a miniature 7-pin base
• 9002 955 with a miniature 7-pin base
• 9003 956 with a miniature 7-pin base
• 9004 Acorn UHF diode
• 9005 Acorn UHF diode with a 3.6 V heater
• 9006 Detector diode with a miniature 7-pin base

List of tubes used in 1920s and 1930s radio receivers

Tubes with directly heated cathodes

Used with AC, DC or home-based storage battery power supplies (1927–1931)

With 1.1 Volt DC filaments

Used in 1920s home radios. Filaments powered by 1.5 volt dry cells, plates powered by storage batteries.

• WD-11 triode/detector

With 2.0 Volts DC filaments

Used in 1930s home radios powered by storage batteries.

• 19 Dual power triode—also used in farm radios with 6-volt vibrator power supplies. Early version of octal type 1J6G.
• 20 Power triode - Early versions numbered UX-120.
• 22 Sharp-cutoff tetrode - Early versions numbered UX-222 or CX-322.
• 25S Dual detector diode, medium-mu triode. Identical to type 1B5. Usually numbered 1B5/25S.
• 30 Medium-mu triode, An upgraded version of type 01-A. - Early versions numbered RCA-230 or CX-330. Can also be used as a power triode. The type 30 was popular amongst amateurs of the day. Early UX4 based version of octal type 1H4G.
• 31 Power triode, UX4 based - Early versions numbered RCA-231 or CX-331.
• 32 Sharp-cutoff tetrode - Early versions numbered RCA-232 or CX-332.
• 33 Power pentode - Early versions numbered RCA-233 or C-333.
• 34 Remote-cutoff tetrode - Early versions numbered RCA-234 or CX-334.
• 49 Dual-grid power triode, similar to type 46

With 3.3 Volts DC filaments

Used in 1920s home radios powered by dry cells (filaments) and storage batteries (B-plus voltage).

• V99 Low-mu triode. Except for stub-pin bayonet base and pinout, electronically similar to X99
• X99 Similar to V99, but with standard pins and different basing arrangement (pinout).

With 5.0 Volts DC filaments

Used in 1920s home radios powered by storage batteries.

• 00-A Detector triode with a trace of argon. "00-A" is the number used in most tube manuals. Numbers for earlier versions include UX-200-A and CX-300-A (long pins, push-in socket) and UV-200-A (stub pins, bayonet socket).
• 01-A All-purpose low-mu triode, used as RF amplifier, detector, AF amplifier and power triode. The most popular tube of the 1920s. "01-A" is the number used for replacements manufactured after 1930 and in tube manuals. Numbers for early versions include UX-201-A and CX-301-A (long pins, push in socket) and UV-201-A (stub pins, bayonet socket).

Note: There were four tubes in the "01" series, each with different current ratings for their filaments. Type 01-A was the most commonly used.

Types UV 201 and UX 201 - 1.0 ampere

Type 01-A (UV 201-A, UX 201-A, etc.) - 250 milliampere

Type UX 201-B - 125 milliampere

Type UX 201-C - 60 milliampere

• 12-A Medium-mu triode, often used as detector, audio driver or audio output, but not as an RF amplifier - This type is listed in tube manuals after 1930 for replacements purposes. Also referred to as type 112-A. Many early versions are marked UX-112-A or CX-112-A.
• 40 Medium-mu triode - Early versions numbered UX-240. Introduced in 1927, this was an upgraded version of the "01" series. The "01" series had an amplification factor of 8, while type 40 had an amplification factor of 30. (By comparison, the two AC triodes introduced in the same time period—types 26 and 27—had amplification factors of 8.3 and 9, respectively.) Because this was the highest-amplification triode available, advertising literature of the time lists it as a high-mu triode, although it is now classified as a medium-mu triode. Type 40 had the highest amplification factor of any triode until the introduction in 1932 of diode/triode complex type 2A6, which had an amplification factor of 100. It also had the highest amplification factor of any DC filament triode until the introduction in 1939 of complementary diode/triode complex types 1H5GT (octal) and 1LH4 (loctal), which both had amplification factors of 65.

Other directly DC-heated tubes

• 2HF Tube-based "integrated circuit" with 2 tetrodes and passive components in the same envelope
• 3NF Tube-based "integrated circuit" with 3 triodes and passive components in the same envelope. 4V heater
• WG38 Tube-based "integrated circuit" with 2 pentodes, a triode and passive components in the same envelope

Directly AC-heated power tubes

• 10 Power triode - Early versions numbered UX-210 or CX-310.
• 26 Medium-mu triode, used in early AC radio receivers manufactured in the late 1920s. Used as an RF or AF amplifier, but not as an dectetor or power output tube. - Early versions numbered UX-226 or CX-326.
• 45 Power Triode - Early versions numbered UX-245 or CX-345.
• 46 Dual grid power triode - Grids 1 and 2 connected together for use as push-pull Class-B outputs, Grid 2 and plate connected together for use as single-tube audio driver.
• 47 Power pentode - Early versions numbered RCA-247 or C-347.
• 50 Power triode - Early versions numbered UX-250 or CX-350.
• 71-A Power triode - This type listed in tube manuals after 1930 for replacements purposes. Also referred to as 171-A. Many early versions numbered as UX-171-A or CX-371-A.

Directly AC-heated rectifier tubes

• 80 Full-wave rectifier used in early power supplies or battery eliminators (electronically similar to 5Y3G) - Early versions numbered UX-280 or CX-380
• 81 Half-wave rectifier - Early versions numbered UX-281 or CX-381.
• 82 Full-wave mercury-vapor rectifier
• 83 Full-wave mercury-vapor rectifier
• 83-V High-vacuum version of type 83, Early UX4 based version of octal type 5V4G.

Tubes with indirectly heated cathodes

With DC heaters

• 15 Sharp-cutoff pentode, used in farm radios, in autodyne circuits requiring a separate cathode.
• 48 Power tetrode, used in 32-volt farm radios. When two are parallel-connected, they can operate with plate and screen voltages as low as 28 volt.

For use with an AC heating transformer

Note: All have 2.5 volt heaters.

• 24 Sharp-cutoff tetrode, UX5 based, Early versions numbered UY-224 and C-324
• 24-A an upgraded version of type 24, see type 24 above. Early versions numbered UY-224A and C-324A
• 27 Medium-mu triode, UX5 based, Early versions numbered UY-227 and C-327. The first North American tube with an indirectly heated cathode, which is necessary for detector circuits in AC powered tube radios.
• 35 Remote-cutoff tetrode, UX5 based, (Commonly branded as 35/51). Early versions numbered UY-235 or C-335
• 51 Similar to 35, see type 35 above. (Commonly branded as 35/51)
• 53 Dual power triodes, Class-B, UX7 based, (Except for heater, electronically similar to 6A6 and octal based 6N7)
• 55 Dual-diode, medium-mu triode, UX6 based, (Except for heater, electronically similar to type 85, and octal based 6V7G, but not to 75)
• 56 Medium-mu triode, UX5 based, (Except for heater, electronically similar to 76, and octal based 6P5G)
• 57 Sharp-cutoff pentode used in cabinet and mantel radio receivers, UX6 based, (Except for heater, electronically similar to 6C6 and octal based 6J7G, and somewhat similar to type 77)
• 58 Remote-cutoff pentode, UX6 based, (Except for heater, electronically similar to 6D6 and octal based 6U7G, but not to 78)
• 59 Power pentode, UX7 based.

For use with AC/DC or vehicle-based storage-battery power supplies

Note: All have 6.3 volt heaters except type 43

• 1-V Half-wave rectifier with indirectly heated cathode, UX4 based, (often branded as type 1V/6Z3). Early version was KR-1.
• 36 Sharp-cutoff tetrode, UX5 based. Early versions numbered RCA-236 or C-336
• 37 Medium-mu triode, UX5 based. Early versions numbered RCA-237 or C-337
• 38 Power pentode, UX5 based. Early versions numbered RCA-238
• 39 Remote-cutoff pentode, UX5 based (Commonly branded as 39/44).
• 41 Power pentode, Early UX6 based version of octal type 6K6G, and loctal type 7B5.
• 42 Power pentode, Early UX6 based version of octal type 6F6G, Except for heater, similar to types 2A5 and 18.
• 43 Power pentode, Early UX6 based version of octal type 25A6G, Commonly used in AC/DC radios.
• 44 Similar to type 39, see type 39 above. (Commonly branded as 39/44).
• 75 Dual-diode, high-mu triode. Early UX6 based version of octal types 6B6G & 6SQ7GT, and loctal type 7B6, and 7-pin miniature type 6AV6. Also except for heater, electronically similar to 2A6.
• 76 Medium-mu triode, Early UX5 based version of octal type 6P5G.
• 77 Sharp-cutoff pentode, Early UX6 based version of octal type 6J7G.
• 78 Remote-cutoff pentode, Early UX6 based version of octal type 6K7G.
• 79 Dual power triode, Early UX6 based version of octal type 6Y7G.
• 84 Full-wave rectifier with indirectly heated cathode, (often branded as type 84/6Z4). Early UX5 based version of octal type 6X5GT, and loctal 7Y4, and 7-pin miniature 6X4.
• 85 Dual-diode, medium-mu triode. Early UX6 based version of octal type 6V7G, except for heater voltage similar to type 55. Also somewhat similar to octal type 6SR7GT and 7-pin miniature types 6BF6.
• 89 Power pentode, UX6 based.

Shielded tubes for Majestic radios

In the early 1930s, the Grigsby-Grunow Company—makers of Majestic brand radios—introduced the first American-made tubes to incorporate metal shields. These tubes had metal particles sprayed onto the glass envelope, copying a design common to European tubes of the time. Early types were shielded versions of tube types already in use. (The shield was connected to the cathode.) The Majestic numbers of these tube types, which are usually etched on the tube's base, have a "G" prefix (for Grigsby-Grunow) and an "S" suffix (for shielded). Later types incorporated an extra pin in the base so that the shield could be connected directly to the chassis.

Replacement versions from other manufacturers, such as Sylvania or General Electric, tend to incorporate the less expensive, form-fitting Goat brand shields that are cemented to the glass envelope.

Grigsby-Grunow did not shield rectifier tubes (except for type 6Y5 listed below) or power output tubes.

• Early types based on existing tubes. (Non-shielded versions may be used, but add-on shielding is recommended.)
  • G-2A7-S Pentagrid converter
  • G-2B7-S Semiremote-cutoff pentode, dual detector diode
  • G-6A7-S Pentagrid converter
  • G-6B7-S Semiremote-cutoff pentode, dual detector diode
  • G-6F7-S Remote-cutoff pentode, medium-mu triode
  • G-25-S Medium-mu triode, dual detector diode for 2.0 volt storage battery radios. Glass type 1B5/25S used for replacement.
  • G-51-S Remote-cutoff tetrode
  • G-55-S Medium-mu triode, dual detector diode
  • G-56-S Medium-mu triode
  • G-56A-S Medium-mu triode, original version of type 76, but with 400 milliampere heater. (Not to be confused with types 56 or G-56-S, which has a 2.5 volt, 1.0 ampere heater.)
  • G-57-S Sharp-cutoff pentode
  • G-57A-S Sharp-cutoff pentode, original version of type 6C6, but with 400 milliampere heater. (Not to be confused with types 57 or G-57-S, which has a 2.5 volt, 1.0 ampere heater.)
  • G-58-S Remote-cutoff pentode
  • G-58A-S Remote-cutoff pentode, original version of type 6D6, but with 400 milliampere heater. (Not to be confused with types 58 or G-58-S, which has a 2.5 volt, 1.0 ampere heater.)
  • G-85-S Similar to G-55-S, but with 6.3 volt heater.
• Later types
  • 6C7 Medium-mu triode, dual detector diode, similar to later octal types 6R7 and 6SR7. Seven pin base. (Shield to pin 3.)
  • 6D7 Sharp-cutoff pentode, identical to type 6C6, but with 7-pin base. (Shield to pin 5.)
  • 6E7 Remote-cutoff pentode, identical to type 6D6, but with 7-pin base. (Shield to pin 5.)
  • 6Y5 Dual rectifier diode, similar to type 84/6Z4, but with 6-pin base. (Shield to pin 2.)

• Other tubes unique to Majestic radios
  • G-2-S and G-4-S Dual detector diodes with common cathodes. The first detector diodes packaged in a separate tube. Forerunners of octal type 6H6. Spray-shielded. Both tubes have 2.5 volt heaters. G-2-S is larger and has a 1.75 ampere heater. Type G-4-S has a 1.0 ampere heater. Later Sylvania replacement type 2S/4S has a 1.35 ampere heater.
  • 2Z2/G-84 Half-wave rectifier diode with 2.5 volt indirectly heated cathode. A lower-voltage version of type 81. Not interchangeable with type 6Z4/84.
  • 6Z5 Full-wave rectifier, similar to types 6Z4/84 and 6X5, but with 12.6 volt center-tapped heater.

Lettered loctal tubes used in Philco radios

• FM-1000 Unusual pentagrid for use as oscillator and coincidence-type phase detector in a PLL FM quadrature detector. The anode signal is loosely coupled into the oscillator tank and pulls it to stay quadrature-phase-locked with the IF; manufactured by Sylvania and used in Philco AM/FM radios of the late 1940s and early 1950s. Predecessor of the nonode approach
• XXB Medium-mu twin triode, also numbered 3C6/XXB
• XXD Medium-mu twin triode, also numbered 14AF7/XXD
• XXFM High-mu triode, twin diode (one shares its cathode with the triode, one with separate cathode), also numbered 7X7/XXFM
• XXL Medium-mu triode, also numbered 7A4/XXL

Rarely used tubes

• 14 Similar to 24-A but with a 14 volt, 300 milliampere heater. Used in Philco models 46 and 46E
• 17 Similar to 27 but with a 14 volt, 300 milliampere heater. Used in Philco models 46 and 46E
• 18 Similar to 2A5 and 42 but with a 14 volt, 300 milliampere heater. No known commercial use.
• 29 Wunderlich detector. Known to have been manufactured by Sylvania.
• 52 Dual grid power triode similar to types 46 and 49. Has 6.3 volt filament. Most commonly used in early car radios.
• 64 Sharp-cutoff tetrode (Except for 400 milliampere heater, similar to 36)
• 65 Remote-cutoff pentode (Except for 400 milliampere heater, similar to 39)
• 67 Medium-mu triode (Except for 400 milliampere heater, similar 37)
• 68 Power pentode (Except for 400 milliampere heater, similar to 38)
• 69 Wunderlich detector
• 70 Wunderlich detector used in Mission Bell model 19 car radio. Listed in early Philco tube lists.
• 90 Wunderlich detector
• 92 Wunderlich detector
• 95 Original number of type 2A5
• 181 Power triode
• 182-B Similar to 482-B below.
• 183 Similar to 483 below.
• 213 Early version of type 80 - Often numbered UX-213
• 216 Early version of type 81 - Often numbered as UX-216-B
• 482-B Power triode with directly heated cathode. Used in Sparton AC radios, circa 1929. Replacements often numbered 182-B/482-B. Similar to type 71-A, but with higher plate voltage.
• 483 Power triode with directly heated cathode. Used in Sparton AC radios, circa 1929. Replacements often numbered 183/483. Similar to type 45, but with a 5.0 volt, 1.25 ampere heater.
• 485 Medium-mu triode with indirectly heated cathode. Used in Sparton AC radios, circa 1929. Similar to types 56 and 76, but with a 3.0 volt, 1.25 ampere heater, and lower plate voltage.

Russian tubes

List of standard tubes, with American equivalents

Note: Typecode explained above.

• 6N1P 6Н1П Dual triode, similar to 6DJ8/ECC88
• 6N2P 6Н2П Dual triode, similar to 12AX7/ECC83
• 6N3P 6Н3П (2C51) Dual triode
• 6N8S 6Н8С (6SN7/ECC33) Dual triode
• 6N9S 6Н9С (6SL7) Dual triode
• 6N13S 6Н13С (6AS7G) Dual power triode
• 6N14P 6Н14П Dual RF/VHF triode, similar to ECC84/6CW7
• 6N23P 6Н23П (6DJ8/ECC88) Dual triode
• 6N24P 6Н24П (ECC89/6FC7/6ES8) Dual RF/VHF triode for cascode amps
• 6P1P 6П1П Power pentode, similar to 6AQ5/EL90
• 6P3S 6П3С Beam-power tetrode, similar to 6L6GB
• 6P3S-E 6П3С-Е Beam-power tetrode, similar to 5881/6L6WGB
• 6P6S 6П6С (6V6) Beam-power tetrode
• 6P14P 6П14П (6BQ5/EL84) Power pentode
• 6S19P 6С19П - Output triode
• 6L1P 6Л1П - Nonode for FM quadrature detection

List of very-high power tubes

Note: Typecode explained above.

ГУ-78Б (GU-78B) Power transmitter tetrode

• G-807 Г-807 Shortwave transmitter tube (the Russian 807 analogue).
• GI-7B ГИ-7Б Impulse tube
• GM-70 ГМ-70 Modulator tube
• GS-31B ГС-31Б UHF transmitter tube
• GU-29 ГУ-29 VHF transmitter tube
• GU-50 ГУ-50 - VHF transmitter pentode, similar to the German LS-50 (no direct U.S. equivalent)
• GU-78B ГУ-78Б VHF transmitter tetrode

List of indicator tubes

• IN-33 ИН-33 Neon-filled, planar, dual 105-segment linear glow-transfer bar graph display tube with three cathode strings, for use in VU meters etc.; similar to PBG16101

⚫	⚫	⚫	⚫
⚫	⚫	⚫	⚫
⚫	⚫	⚫	⚫
⚫	⚫	⚫	⚫

• ITM2-M ИТМ2-М Four-color phosphored-thyratron latching pixel; 4x4 array of 4 subminiature dual-starter luminiscent thyratrons each for the colors red, yellow, green and blue (thus, 5 intensities per color yields 5⁴ = 625 colors), 4x4 matrix of 10-volts sensitive starter electrodes, cubic envelope for easy stacking in both axes, 12-pin all-glass pigtaled, similar to today's RGBA LEDs
• ITS1A ИТС1А Green phosphored-thyratron latching seven-segment display, no decimal point, 5-volts sensitive starter electrodes, all-glass pigtaled, rectangular envelope for easy stacking in both axes
• MTX-90 МТХ-90 Small neon-filled thyratron for use as a latching single-dot indicator, top-viewing, top of envelope acts as a magnifier, all-glass pigtaled, comes with a blob of solder on the end of each wire for rapid installing, like today's ball grid arrays

List of other tubes

• LP-4 ЛП-4 Linear trochotron, 26-pin Acorn-type all-glass pigtaled,

References

• Frank Philipse's Tube Datasheet Archive
  • Mirrors in Germany, Germany, Japan^[incomplete], Hong Kong, Hong Kong, Hungary, Poland, Poland searchable, Sweden, USA^[incomplete], USA^[incomplete]
• Roy J. Tellason's tube datasheet collection
• Tubebooks.org datasheet collection
• General Electric Essential Characteristics, 1970

• RCA Receiving Tube Manuals R10 (1932), RC11 (1933), RC12 (1934), RC13 (1937), RC14 (1942), RC15 (1948), RC16 (1951), RC17 (1954), RC18 (1956), RC19 (1959), RC20 (1960), RC21 (1961), RC22 (1963), RC23 (1964), RC24 (1965), RC25 (1966), RC26 (1968), RC27 (1970), RC28 (1971), RC29 (1973), RC30 (1975)
• Sylvania Technical Manual, 1958
• J. P. Hawker (ed), Radio and television servicing, Newnes, London, 1964

Wikimedia Commons has media related to: Vacuum tubes or Gas discharge tube

External links

• Vacuum Tube Data Sheet Locator
• Tube Substitution and Characteristics Guide
• Scanned tube documentation (PDFs): Tubebooks, Frank Philipse, 4tubes
• British virtual thermionic valve museum with good quality pictures and data
• Radio museum
• Virtual Valve Museum
• Camera tube datasheets

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• Decoding type numbers
• European tube designation systems: [1], [2]