250+ TOP MCQs on Bridge Rectifier and Answers

Electronic Devices and Circuits Multiple Choice Questions on “Bridge Rectifier”.

1. DC average current of a bridge full wave rectifier (where I_m is the maximum peak current of input).
A. 2I_m
B. I_m
C. I_m/2
D. 1.414I_m
Answer: B
Clarification: Average DC current of half wave rectifier is I_m. Since output of half wave rectifier contains only one half of the input. The average value is the half of the area of one half cycle of sine wave with peak I_m. This is equal to I_m.

2. DC power output of bridge full wave rectifier is equal to (I_m is the peak current and RL is the load resistance).
A. 2 I_m²R_L
B. 4 I_m²R_L
C. I_m²R_L
D. I_m² R_L/2
Answer: B
Clarification: DC output power is the power output of the rectifier. We know V_DC for a bridge rectifier is 2V_m and I_DC for a bridge rectifier is 2I_m. We also know V_DC=I_DC/R_L. Hence output power is 4I_m²R_L.

3. Ripple factor of bridge full wave rectifier is?
A. 1.414
B. 1.212
C. 0.482
D. 1.321
Answer: C
Clarification: Ripple factor of a rectifier measures the ripples or AC content in the output. It’s obtained by dividing AC rms output with DC output. For full wave bridge rectifier it is 0.482.

4. If input frequency is 50Hz then ripple frequency of bridge full wave rectifier will be equal to_________
A. 200Hz
B. 50Hz
C. 45Hz
D. 100Hz
Answer: D
Clarification: Since in the output of bridge rectifier one half cycle is repeated, the frequency will be twice as that of input frequency. So, f=100Hz.

5. Transformer utilization factor of bridge full wave rectifier _________
A. 0.623
B. 0.812
C. 0.693
D. 0.825
Answer: B
Clarification: Transformer utilization factor is the ratio of AC power delivered to load to the DC power rating. This factor indicates effectiveness of transformer usage by rectifier. For bridge full wave rectifier it’s equal to 0.693.

6. If peak voltage on a bridge full wave rectifier circuit is 5V and diode cut in voltage os 0.7, then the peak inverse voltage on diode will be_________
A. 4.3V
B. 9.3V
C. 8.6V
D. 3.6V
Answer: D
Clarification: PIV is the maximum reverse bias voltage that can be appeared across a diode in the circuit. If PIV rating of diode is less than this value breakdown of diode may occur.. Therefore, PIV rating of diode should be greater than PIV in the circuit, For bridge rectifier PIV is V_m-V_D = 5-1.4=3.6.

7. Efficiency of bridge full wave rectifier is_________
A. 81.2%
B. 50%
C. 40.6%
D. 45.33%
Answer: A
Clarification: It’s obtained by taking ratio of DC power output to maximum AC power delivered to loaC. Efficiency of a rectifier is the effectiveness of rectifier to convert AC to DC. It’s usually expressed inn percentage. For bridge full wave rectifier, it’s 81.2%.

8. In a bridge full wave rectifier, the input sine wave is 40sin100t. The average output voltage is_________
A. 22.73V
B. 16.93V
C. 25.47V
D. 33.23V
Answer: C
Clarification: The equation of sine wave is in the form E_msinωt.
Therefore, E_m=40. Hence output voltage is 2E_m=80V.

9. Number of diodes used in a full wave bridge rectifier is_________
A. 1
B. 2
C. 3
D. 4
Answer: D
Clarification: The model of a bridge rectifier is same as Wein Bridge. It needs 4 resistors. Bridge rectifier needs 4 diodes while centre tap configuration requires only one.

10. In a bridge full wave rectifier, the input sine wave is 250sin100t. The output ripple frequency will be_________
A. 50Hz
B. 200Hz
C. 100Hz
D. 25Hz
Answer: C
Clarification: The equation of sine wave is in the form of E_msinωt. So, ω=100 and frequency (f)=ω/2=50Hz. Since output of bridge rectifier have double the frequency of input, f=100Hz.