250+ TOP MCQs on Type D Chopper and Answers

Power Electronics Multiple Choice Questions on “Type D Chopper”.

1. A type D chopper is a
A. two quadrant type-B chopper
B. two quadrant type-A chopper
C. two quadrant type-C chopper
D. none of the mentioned

Answer: A
Clarification: It is a two quadrant (I and IV) type B chopper as load current is always positive but the voltage can be positive or negative.

2. In a type-D chopper
A. current can flow in both the directions of the load
B. current cannot flow in both the directions of the load
C. voltage can only be positive
D. voltage can only be negative

Answer: B
Clarification: It is a two quadrant (I and IV) type B chopper. In quadrant I and IV current is only positive.

3. For a type D chopper, the average value of output voltage will be positive when
A. T_on = T_off
B. T_onoff
C. T_off = 0
D. T_on > T_off

Answer: D
Clarification: When the chopper on time (SW1 and SW2) is more than the chopper off time than the average voltage will be positive. When the chopper switches are off, both the diodes are operating and the voltage is negative.

4. For a type D chopper, if duty cycle = 0.5 then the
A. average voltage is positive
B. average voltage is negative
C. average voltage is zero
D. chopper cannot be operated with duty cycle = 0.5

Answer: C
Clarification: When α = 0.5. T_on = T_off hence the positive and negative value of voltages become equal. Making the average voltage = 0 V.

5. For a type D chopper, if duty cycle α < 0.5 then the
A. average voltage is positive
B. average voltage is negative
C. average voltage is zero
D. none of the mentioned

Answer: B
Clarification: α = T_on/T
If α < 0.5, T_onoff
The average value of voltage will be negative, as the switches will be off most of the times.

6. Find the average output voltage for a type D chopper if it is given a dc supply of 220 V. Chopper frequency is 2 kHz and both the chopper switches are operated for 0.3 ms.
A. 220 V
B. 108 V
C. 98 V
D. 44 V

Answer: D
Clarification: T = 1/f = 0.5 ms
Ton = 0.3 ms
Toff = 0.2 ms
Vo = Vs (Ton – Toff)/T = 220 x (1/5) = 44 V.

7. Find the expression for average output voltage in a type D chopper on RL load.
A. Vs x Duty cycle (α)
B. Vs x T
C. Vs x (T – T)/T
D. Vs2/2

Answer: C
Clarification:
During Ton = Vs x Ton/T
During Toff = – Vs x Toff/T
Vo = Vs (Ton – Toff)/T.