electrical engineering MCQs – Page 243

Practise multiple-choice questions from electrical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

electrical engineering Mcqs
1. economics of power generation2. analog electronics3. solid state switching circuits4. parallel circuits5. switchgear and protection6. op amp circuits7. transistor audio power amplifiers8. electrostatics9. heating and welding10. multi stage transistor amplifiers11. passive filters12. network theorems13. regulated d c power supply14. a c fundamentals circuits and circuit theory15. electromagnetic induction16. power electronics17. magnetism and electromagnetism18. transformers19. modulation and demodulation20. d c generators21. semiconductor theory22. single phase induction motors23. semiconductor diode24. hybrid parameters25. digital electronics26. oscillators27. earthing or grounding28. single stage transistor amplifiers29. d c motors30. transistor biasing31. amplifiers with negative feedback32. basic electrical33. electronic instruments34. synchronous motors35. field effect transistors fet36. magnetic circuit37. control systems38. industrial drives39. power generation40. series parallel circuits41. transistor tuned amplifiers42. electrical engineering materials43. rectifiers and converters44. integrated circuits45. scr silicon controlled rectifiers46. cables47. polyphase induction motors48. measurement and instrumentation49. transistors50. electrical machine design51. electrolysis and storage of batteries52. electric traction53. transmission and distribution
4841. Gate circuit or triggering circuit of a thyristor is
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A. high power circuit.

B. may be low power or high power circuit

C. lower power circuit.

D. magnetic circuit.

4842. SCR will be turned off when anode current is_______________?
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A. < latching current but greater than holding current and gate signal is 0.

B. less than holding current.

C. < latching current but greater than holding current and gate signal is present.

D. both (A) and (B).
4843. The ability of an electronic system to function properly in its intended electromagnetic environment and should not be a source of pollution to that electromagnetic environment is known as____________?
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A. Interference

B. Susceptibility

C. Emission

D. Electromagnetic compatibility
4844. In current commutated DC-DC choppers, the voltage spike appears across the load when_____________?
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A. Voltage across the commutating inductances collapses

B. The capacitance voltage adds to the supply voltage

C. Both A. and B.

D. None of these

4845. In a lossless inverter, the average power absorbed in one period by the load must be__________?
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A. Equal to the average power supplied by the dc source

B. Greater than the average power supplied by the dc source

C. Equal to the average power supplied by the ac source

D. Lesser than the average power supplied by the dc source

4846. The latching current of GTO should be of order
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A. 100 mA

B. 500 mA

C. 1:00 AM

D. 2:00 AM

4847. Typical range of thyristor turn OFF time is______________?
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A. 3 10 s

B. 3 50 s

C. 3 500 s

D. 3 100 s
4848. With increase in firing angle,
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A. Both harmonic distortion and quality of input current increases

B. Harmonic distortion increases and quality of input current decreases

C. Harmonic distortion decreases and quality of input current increases

D. Both harmonic distortion and quality of input current decreases

4849. Which statement is true for latching current ___________?
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A. t is related to turn off process of the device.

B. It is related to conduction process of device.

C. It is related to turn on process of the device.

D. Both C and D.

4850. Number of PN junction in an SCR is____________?
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A. Three

B. Four

C. Two

D. Five

4851. During the commutation period in 3 phase converter, overlap time is_____________?
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A. Dependent on the load current

B. Dependent on the voltage

C. Dependent on both the load current and load voltage behind the short circuit current

D. Independent on both the load current and load voltage

4852. In a single phase full wave rectifier, during blocking state the pea inverse voltage of diode is______________?
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A. V m / 2

B. 4 V m

C. V m

D. 2 V m
4853. Which of following is not a power transistor?
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A. IGBTs

B. SITS

C. TRIAC

D. COOLMOS

4854. In a three phase converter, the number of notches per cycle is____________?
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A. Six

B. One

C. Three

D. Nine

4855. What may happen high dV / dt____________?
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A. Unwanted turn ON

B. Breakdown of J2 junction

C. Both A and B

D. Anyone of these

4856. What is used to protect a thyristor from high di / dt conditions__________?
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A. Inductor

B. Fuse.

C. Voltage clamping device

D. Snubber circuit

4857. Regulator sampling PWM is usually used in___________?
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A. High power inverters

B. Rectifiers

C. Low power inverters

D. Only A. and B.
4858. Under normal operating condition voltage clamping device offers impedance of_________?
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A. high value.

B. low value.

C. moderate value.

D. zero value.

4859. The maximum di/dt in a SCR is____________?
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A. Directly proportional to supply voltage

B. Directly proportional to inductance in the circuit

C. Inversely proportional to supply voltage

D. Both A and B
4860. In EMC signal, the source delivers maximum power to the input of transmission line when the transmission line input impedance
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A. None of these

B. Is equal to the source resistance

C. Smaller than the source resistance

D. Greater than the source resistance