ELECTRONIC INSTRUMENTATION

INTERNATIONAL INSTITUTE OF MANAGEMANT & TECHNICAL STUDIES QUESTION PAPER ELECTRONIC INSTRUMENTATION Max Marks:100 Note: Question number 1-5 carries 2 Marks Question number 6-15 carries 3 Marks Question number 16-20 carries 12 Marks Q.1. Which of the following instruments indicate the instantaneous value of the electrical quantity being measured at the time at which it is being measured ? (a) Absolute instruments (b) Indicating instruments (c) Recording instruments (d) Integrating instruments Q.2.Which of the following are integrating instruments ? (a) Ammeters (b) Voltmeters (c) Wattmeters (d) Ampere-hour and watt-hour meters Q.3. Most common form of A.C. meters met with in every day domestic and industrial installations are (a) mercury motor meters (b) commutator motor meters (c) induction type single phase energy meters (d) all of the above Q.4. The disc of an instrument using eddy current damping should be of (a) conducting and magnetic material (b) non-conducting and magnetic material (c) conducting and non-magnetic material (d) none of the above Q.5. The resistance in the circuit of the moving coil of a dynamometer wattmeter should be (a) almost zero (b) low (c) high (d) none of the above Q.6. In a low power factor wattmeter the pressure coil is connected (a) to the supply side of the current coil (b) to the load side of the current coil (c) in any of the two meters at connection (d) none of the above Q.7.A 0-300V voltmeter has the error of +_ 2% of FSD.What would be the range of reading if true voltage is 30V (a) 24-30V (b) 29.4-30.6V (c) 20-30V (d) none of the above Q.8.A d’arsonval movement is rated at 50 microA .Its sensitivity is : (a) 20000 ohm/V (b) 200000ohm/V (c) 200 ohm/V (d)None of the above Q.9. In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was (a) unity (6) 0.8 lagging (c) 0.8 leading (d) zero Q.10. The adjustment of position of shading bands, in an energy meter is done to provide (a) friction compensation (b) creep compensation (c) braking torque (d) none of the above Q.11. The electrical power to a meggar is provided by (a) battery (b) permanent magnet D.C. generator (c) AC. generator (d) any of the above Q.12. It is required to measure the true open circuit e.m.f. of a battery. The best device is (a) D.C. voltmeter (b) Ammeter and a known resistance (c) D.C. potentiometer (d) None of the above Q.13. To measure a resistance with the help of a potentiometer it is (a) necessary to standardise the potentiometer (b) not necessary to standardise the potentiometer (c) necessary to use a volt ratio box in conjunction with the potentiometer (d) none of the above Q.14. In order to achieve high accuracy, the slide wire of a potentiometer should be (a) as long as possible (b) as short as possible (c) neither too small not too large (d) very thick Q.15. In an AC. co-ordinate potentiometer, the currents in the phase and quadrature potentiometer are adjusted to be (a) out of phase by 90° (6) out of phase by 60° (c) out of phase by 30° (d) out of phase by 0° (e) out of phase by 180° Q.16 (A).Explain any two methods for measurement of medium measurement. Q.16 (B). In a potentiometer system with a standard cell of emf of 1.08 V, the galvanometer shows zero deflection for a balanced point of 100 cm. What is the emf of a cell which balances at 150 cm? Q.17. A Crompton potentiometer consist of resistance dial having 15 steps of 10 Ω each and a series connected slide wire of 10 Ω is divided in 100divisions.If the working current of potentiometer is 10mA and each division of slide wire can be rea accurately upto 1/5 of its span,calculate the resolution of potentiometer Q.18(A).Explain de sauty’s bridge with help of balance equation? Q.18 (B).Explain how the range of ammeter can be increased? Q.19(A). Explain the electro dynamo meter type instrument with derivation. Q.19(B).Explain the operation of ac voltmeter using half wave rectifier and full wave rectifier. Q.20(A). Discuss different type of Standards of measurement. Classify and explain the different type of Standards of measurement. Q.20(B). Explain with block diagram, the operation of ramp type DVM. Guideline – Ensure to solve every question in series. Do not copy past answers, as it will lead to rejection of answer sheets. Make sure to write enough length answers of descriptive questions as per the weightage. Highlight more relevant case studies and practice examples. Submit answer sheet in standard format only. Make sure to be in time limits of submission to avoid rejection of submission after deadline. In case of hand written sheet submission please be assure of sober writing and cleanliness of answer sheet. Do take care of numerical and diagrammatical representation up to the mark if applicable.