SCR MCQ | Thyristor MCQ

31. SCR in its normal operation works in ________.

  1. Forward blocking mode
  2. Reverse blocking mode
  3. Forward conduction mode
  4. Reverse breakover mode
Answer
Answer. c

32. Class B commutation technique in SCR is-

  1. Self-commutation by a resonating load
  2. C or L-C switched by another load-carrying SCR
  3. Self-commutated by an L-C circuit
  4. An AC line commutation
Answer
Answer. c

33. What does the maximum surge current rating of an SCR specify?

  1. Repetitive current with sine wave
  2. Non-repetitive current with rectangular wave
  3. Non-repetitive current with sine wave
  4. Repetitive current with rectangular wave
Answer
Answer. c

34. A conducting SCR can be opened by reducing _________ to zero.

  1. Supply current
  2. Supply voltage
  3. Anode current
  4. Grid voltage
Answer
Answer. c

35. For dynamic equalizing circuit used for series-connected SCRs, the choice of C is based on

  1. Rise time characteristics
  2. Turn on charateristics
  3. Turn off characteristics
  4. Reverse recovery characteristics
Answer
Answer. d

36. The protection used for SCR in case of high di/dt is

  1. Parallel capacitor
  2. Series inductance
  3. Snubber circuit
  4. Fast-acting fuse
Answer
Answer. b

37. Which one of the following is used as an active device in an electronic circuit?

  1. Transformer
  2. Electric heater
  3. SCR
  4. Loudspeaker
Answer
Answer. c

38. SCR is a ________ layer _________ junction device.

  1. Single, three
  2. Two, four
  3. Three, four
  4. Four, three
Answer
Answer. d

39. When cathode is positive with respect to anode in an SCR, the number of blocked p-n junctions is

  1. 4
  2. 3
  3. 2
  4. 1
Answer
Answer. b

40. The snubber circuit is used in the thyristor circuit for

  1. phase shifting
  2. dv/dt protection
  3. di/dt protection
  4. triggering
Answer
Answer. b
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