# Diode Circuits-Basic Electronics Engineering MCQs With Answers Part 2

## This is part 2 of the MCQs of Basic Electronics Engineering. This contains mcqs on topic Diode Circuits. Contains most important and most asked questions.

Click to read part 1 of Diode Circuits

Before solving this questions I suggest you must read this basic electronics

1.The ideal value of reverse resistance of diode is
a. high
b. infinite
c. zero   d. very low

Ans: b

2.The ideal value of forward resistance of diode is
a. high
b. infinite
c. zero
d. very low

Ans: c

3.Rectifier converts
a. a.c. voltage to d.c.voltage
b. a.c voltage to pulsating d.c voltage
c. d.c voltage to a.c. voltage
d. a.c voltage to a.c voltage

Ans: b

4.Efficiency of half wave rectifier is
a. 81.20%
b. 40.60%
c. 45.6 %
d. 82.10%

Ans: b

5.No. of diodes used in full wave rectifier is
a. 1
b. 2
c. 3
d. 4

Ans: b

6.In a full-wave rectifier, the current in each of the diodes flows for
a. the complete cycle of the input signal
b. half cycle of the input signal
c. less than half cycle of the input signal
d. zero time

Ans: b

7.The peak value of the input to a half wave rectifier is 10V. the approximate peak value of the output is
a. 10 V
b. 3.18V
c. 10.7V
d. 9.3V

Ans: d

8.The total secondary voltage in a centre tapped full wave rectifier is 125 V rms. Neglecting the diode drop, the rms output voltage is
a. 125V
b. 177V
c. 100V
d. 62.5V

Ans: d

9. a half-wave rectifier, the peak value of the ac voltage across the secondary of the transformer is 20√2 V. If no filter circuit is used, the maximum dc voltage across the load will be
a. 28.28 V
b. 14.14 V
c. 20 V
d. 9 V

Ans: d

10.What is the frequency of the capacitor ripple voltage in a full-wave rectifier circuit if the frequency of the transformer secondary voltage is 60 Hz?
a. 60Hz
b. 50Hz
c. 120Hz
d. this is impossible to determine

Ans: c

11.What is the dc output voltage of an unfiltered half-wave rectifier whose peak output voltage is 9.8 V?
a. 6.23 V
b. 19.6 V
c. 9.8 V
d. 3.1 V

Ans: d

12.If Vm is the peak voltage across the secondary of the transformer in a half-wave rectifier(without any filter circuit. , then the maximum voltage on the reverse biased diode is
a. Vm
b. ½. Vm
c. 2 Vm
d. none of the above

Ans: a

13.If you are checking a 60 Hz full wave bridge rectifier and observe that the output has 60Hz ripple
a. the circuit is working properly
b. there is an open diode
c. the transformer secondary is shorted
d. the filter capacitor is leaky

Ans: b

14.Efficiency of half wave rectifier is
a. 81.20%
b. 40.60%
c. 45.60%
d. 82.1 %

Ans: b

15.Ripple factor of full wave rectifier is
a. 0.122
b. 0.4
c. 0.48    d. 0.05
Ans: c

16.Efficiency of bridge rectifier is
a. 81.2 %
b. 40.6 %
c. 45.60%
d. 82.1 %

Ans: a

17.In an unbiased PN-junction, the junction current at equilibrium is
a. due to diffusion of minority carriers only
b. due to diffusion of majority carriers only
c. zero, because equal but opposite carriers are crossing the junction
d. zero, because no charges are crossing the junction

Ans: c

18.If Vm is the peak voltage across the secondary of the transformer in a full-wave rectifier with a shunt capacitor filter circuit, then the maximum voltage on the reverse biased diode is
a. Vm
b. ½. Vm
c. 2 Vm
d. both A and B

Ans: c

19.What is the dc output voltage of an unfiltered half-wave rectifier whose peak output voltage is 9.8 V?
a. 6.23 V
b. 19.6 V
c. 9.8 V
d. 3.1 V

Ans: d

20.What is the frequency of the capacitor ripple voltage in a full-wave rectifier circuit if the frequency of the transformer secondary voltage is 60 Hz?
a. 60Hz
b. 50 Hz
c. 120 Hz
d. this is impossible to determine

Ans: c

21.The output from an unfiltered half-wave or full wave rectifier is --
a. a pulsating dc
c. smooth dc voltage
d. none of the above

Ans: a

22.What is the approximate dc output voltage from a filtered bridge rectifier whose peak output voltage is 30V?
a. 19.1 V
b. 9.5 V
c. 30 V
d. none of the above

Ans: c

23.A half wave rectified sinusoidal waveform has a peak voltage of 12V. Its average value and rms value of the fundamental components are; respectively given by
a. 15/p V, 7.5 V
b. 20/p V, 10/Ö2 V
c. 12/p V, 6 V
d. none of these

Ans: c

24.In a bridge rectifier circuit we use

a. no centre-tapping and diode having peak inverse voltage Vm
b. no centre tapping and diode having inverse voltage 2Vm
c. centre tapping and diode having reverse voltage Vm
d. centre- tapping and diode having reverse voltage 2Vm

Ans: a

25.A device converting a.c. to d.c. is called
a. comparator
b. inverter
c. rectifier
d. regulator

Ans: c

26. PIV rating of diode in a bridge rectifier is
a. Vm
b. 2Vm
c. Vm/2
d. none of these

Ans: a

27.In HWR the peak value of ac voltage across secondary of transformer is 20√2 V if no filter circuit is used, the maximum d.c. voltage across the load will be
a. 28.28 V
b. 14.14 V
c. 20 V
d. 9 V

Ans: d

28. If Vm is the peak voltage across secondary of transformer in HWR (without any filter circuit. ,
then the maximum voltage on reverse biased diode is

a. Vm
b. 1/2Vm
c. 2Vm
d. none of the above

Ans: a

29. If Vm is the peak voltage across secondary of transformer in HWR ,if we use shunt capacitor filter, the maximum voltage that occurs on reverse biased diode is
a. Vm
b. 1/2Vm
c. 2Vm
d. none of the above

Ans: a

30.In Center tap FWR Vm is the peak voltage between center tap and one end of secondary, the maximum voltage that occurs on reverse biased diode is
a. Vm
b. 1/2Vm
c. 2Vm
d. none of the above

Ans: c

31.In HWR the load current flows for
a. the complete cycle of input signal.
b. only for positive half cycle of input signal.
c. less than half cycle of input signal.
d. more than half cycle but lass than complete cycle of input signal.

Ans: b

32.What is the dc output voltage of an unfiltered half-wave rectifier whose peak output voltage is 9.8 V?
a. 6.23 V
b. 19.6 V

c. 9.8 V
d. 3.1 V

Ans : d

33.What is the frequency of the capacitor ripple voltage in a full-wave rectifier circuit if the frequency of the transformer secondary voltage is 60 Hz?
a. 60Hz
b. 50 Hz
c. 20 Hz
d. this is impossible to determine

Ans: c

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