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1. DC average current of a bridge full wave rectifier
(Where Im is the maxImum peak current of input)
a) 2Im/ᴨ
b) Im/ᴨ
c) Im/2ᴨ
d) 1.414Im/ᴨ

View Answer

Answer: a [Reason:] Average DC current is the average current in the output of rectifier. For a bridge full wave rectifier, if a sinusoidal input is given output will contain only one half cycle repeatedly. So average current will be twice as half wave rectifier.

2. DC power output of bridge full wave rectifier is equal to
(Im is the peak current and RL is the load resistance)
a) (2Im2/ ᴨ2)RL
b) (4Im2/ ᴨ2)RL
c) (Im2/ ᴨ2)RL
d) (Im2/2 ᴨ2)RL

View Answer

Answer: b [Reason:] DC output power is the power output of the rectifier. It is equal to VDCIDC. We know VDc for a bridge rectifier is 2Vm/ᴨ and IDC for a bridge rectifier is 2Im/ᴨ. We also know VDC = IDC/RL. Hence output power is (4Im2/ ᴨ2)RL

3. Ripple factor of bridge full wave rectifier is
a) 1.414
b) 1.212
c) 0.482
d) 1.321

View Answer

Answer: c [Reason:] Ripple factor of a rectifier measures the ripples or AC content in the output. It is 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

View Answer

Answer: d [Reason:] Since in the output of bridge rectifier one half cycle is repeated hence frequency will twice as that of input frequency. That is 100Hz.

5. Transformer utilization factor of a bridge full wave rectifier is equal to
a) 0.623
b) 0.812
c) 0.693
d) 0.825

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Answer: b [Reason:] 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 is equal to 0.693.

6. If peak voltage on a bridge full wave rectifier circuit is 5V and diode cut-in voltage is 0.7, then peak inverse voltage on diode will be
a) 4.3V
b) 9.3V
c) 8.6V
d) 3.6V

View Answer

Answer: d [Reason:] PIV is the maximum reveres bias voltage that can be appeared across a diode in the circuit. If PIV rating of the 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 Vm-2VD. ie 5-1.4.

7. Efficiency of bridge full wave rectifier is
a) 81.2%
b) 50%
c) 40.6%
d) 45.3%

View Answer

Answer: a [Reason:] It is obtained by taking ratio of DC power output to maximum AC power delivered to load. Efficiency of a rectifier is the effectiveness of rectifier to convert AC to DC. It is usually expressed in percentage. For bridge full wave rectifier, it is 81.2%.

8. In an bridge full wave rectifier, the input sine wave is 40sin100 ᴨt. The average output voltage is
a) 22.73V
b) 16.93V
c) 25.47V
d) 33.23V

View Answer

Answer: c [Reason:] The equation of sine wave is in the form Em sin wt. Therefore, Em=40 Hence output voltage is 2Em/ ᴨ. That is 80/ ᴨ.

9. Number of diodes used in a full wave bridge rectifier is
a) 1
b) 2
c) 4
d) 6

View Answer

Answer: c [Reason:] The model of bridge rectifier is same as weibridge. Like weinbridge needs 4 resistors bridge rectifier needs 4 diodes while center tap configuration requires only one.

10. In an bridge full wave rectifier, the input sine wave is 250sin100 ᴨt. The output ripple frequency of rectifier will be
a) 50Hz
b) 200Hz
c) 100Hz
d) 25Hz

View Answer

Answer: c [Reason:] The equation of sine wave is in the form Em sin wt. Therefore, w = 100ᴨ that is, frequency f = w/2ᴨ = 50Hz Since output of full wave bridge rectifier have double the frequency of input, output frequency is 100Hz.