Electron gun

An electron gun (also called electron emitter) is an electrical component in some vacuum tubes that produces a narrow, collimated electron beam that has a precise kinetic energy. The largest use is in cathode ray tubes (CRTs), used in nearly all television sets, computer displays and oscilloscopes that are not flat-panel displays. They are also used in FED displays, which are essentially flat-panel displays made out of rows extremely small cathode ray tubes. They are also used in microwave linear beam vacuum tubes such as klystrons, inductive output tubes, travelling wave tubes, and gyrotrons, as well as in scientific instruments such as electron microscopes and particle accelerators. Electron guns may be classified by the type of electric field generation (DC or RF), by emission mechanism (thermionic, photocathode, cold emission, plasmas source), by focusing (pure electrostatic or with magnetic fields), or by the number of electrodes.

Characteristics

A direct current, electrostatic thermionic electron gun is formed from several parts: a hot cathode, which is heated to create a stream of electrons via thermionic emission, electrodes generating an electric field which focus the beam (such as a Wehnelt cylinder), and one or more anode electrodes which accelerate and further focus the electrons. A large voltage between the cathode and anode accelerates the electrons. A repulsive ring placed between them focuses the electrons onto a small spot on the anode at the expense of a lower extraction field strength on the cathode surface. Often at this spot is a hole so that the electrons that pass through the anode form a collimated beam and finally reach a second anode called a collector. This arrangement is similar to an Einzel lens.

Róg

Róg may refer to:

RG

RG, Rg or rg may stand for any of the following things:

Military

Persons

Places

Science and technology

Raga

A raga or raag (literally "color, hue" but also "beauty, melody"; also spelled raaga, ragam; pronounced rāga, or rāgam or "raag") is one of the melodic modes used in Indian classical music.

A raga uses a series of five to nine musical notes upon which a melody is constructed. However, the way the notes are approached and rendered in musical phrases and the mood they convey are more important in defining a raga than the notes themselves. In the Indian musical tradition, rāgas are associated with different times of the day, or with seasons. Indian classical music is always set in a rāga. Non-classical music such as popular Indian film songs and ghazals sometimes use rāgas in their compositions.

Joep Bor of the Rotterdam Conservatory of Music defined Raga as "tonal framework for composition and improvisation."Nazir Jairazbhoy, chairman of UCLA's department of ethnomusicology, characterized ragas as separated by scale, line of ascent and descent, transilience, emphasized notes and register, and intonation and ornaments.Pandit Jasraj describes the meaning of Raga as "love".