SCR MCQ | Thyristor MCQ

21. For an SCR with turn-on time of 5 microseconds, an ideal trigger pulse should have

1. Short rise time with pulse width = 3 μsec
2. Long rise time with pulse width = 6 μsec
3. Short rise time with pulse width = 6 μsec
4. None of the above

22. When the SCR conducts, the forward voltage drop will

1. 0.7 V at all load current
2. 2 V to 2.5 V at all load current
3. Increases slightly with load current
4. Remains constant with load current

23. The average gate power dissipation for an SCR is 0.5 W. Gate voltage variation is 2V to 10V. Which of the following is true?

1. Vg = 2 V, Ig = 0.25A
2. Vg = 2 V, Ig = 0.05A
3. Vg = 2 V, Ig = 10 A
4. None of the above

24. Which semiconductor device behaves like to SCR’s?

1. JFET
2. UJT
3. Triac
4. MOSFET

25. The number of p-n junctions in a thyristor (SCR) is/are

1. 1
2. 2
3. 3
4. 4

26. The di/dt rating of an SCR is specified for its

1. Decaying anode current
2. Decaying gate current
3. Rising gate current
4. Rising anode current

27. When SCR starts conducting, then _____ loses all control.

1. Gate
2. Cathode
3. Anode
4. None of these

28. Circuit turn-off time of an SCR is defined as the time

1. Taken by the SCR turn to be off
2. Required for the SCR current to become zero
3. For which the SCR is reverse biased by the commutation circuit
4. For which the SCR is reverse biased to reduce its current below the holding current

29. Which one of the following devices can be turned ‘ON’ or ‘OFF’ by applying a gate signal?

1. SCR
2. SCS
3. Triac
4. UJT

30. An SCR triggered by current pulse through its gate can be turned off by

1. Giving another pulse of the same polarity to the gate
2. By giving pulse to the cathode
3. By giving pulse to the anode
4. By reversing the polarity of anode and cathode voltage