  # Diode Circuits-Basic Electronics Engineering MCQs With Answers Part 3

## This is part 3 of the MCQs of Basic Electronics Engineering. This contains mcqs on topic Diode Circuits. Contains most important and most asked questions.

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

1.In a full-wave rectifier, the dc load current equals 1A. How much dc current is carried by each diode?

a. ½ A
b. 1 A
c. 2 A
d. 0 A

Ans: a

2.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

3.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

4.In a full wave rectifier with R-C filter,
a. 0
b. less than 180
c. Equal to 180
d. More than 0

Ans: b

5.The average value of a half wave rectified voltage with a peak value of 200V is
a. 63.7V
b. 127.3 V
c. 141V
d. 0V

Ans : a

6.When a 60 Hz sinusoidal voltage is applied to the input of a half wave rectifier, the output frequency is
a. 120 Hz
b. 30 Hz
c. 60 Hz
d. 0 Hz

Ans : c

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. 3.18 V
c. 10.7 V
d. 9.3 V

Ans :d

8.The average value of full wave rectified voltage with a peak value of 75V is
a. 53 V
b. 47.8 V
c. 37.5 V
d. 23.9 V

Ans :b

9.When a 60Hz sinusoidal voltage is applied to the input of a full wave rectifier, the output frequency is
a. 120 Hz
b. 60 Hz
c. 240 Hz
d. 0 V

Ans : a

10.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. 177 V
c. 100 V
d. 62.5 V

Ans : d

11.When the peak output voltage is 100V, the PIV for each diode in a centre- tapped full wave rectifier is( neglecting the diode drop.
a. 100 V
b. 200 V
c. 141 V
d. 50V

Ans : b

12.When the rms output voltage of a bridge full-wave rectifier is 20V, the peak –inverse voltage across the diodes is ( neglecting the diode drop.
a. 20 V
b. 40 V
c. 28.3 V
d. 56.6 V

Ans : c

13.A 60 V peak full wave rectified voltage is applied to a capacitor input filter. If f=120 voltage is
a. 0.6 V
b. 6 mV
c. 5 V
d. 2.88 V

Ans : d

14.If one of the diodes in a bridge full wave rectifier opens, the output is
a. 0V
b. one-fourth the amplitude of the input voltage
c. a half wave rectified voltage
d. a 120Hz voltage

Ans : c

15.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
16.With a half wave rectified voltage across the load resistor, load current flows for what part of a cycle?
a. 0 degree

b. 90 degree
c. 180 degree
d. 360 degree

Ans : c

17.Suppose line voltage may be as low as 105 V rms or as high as 125 V rms in a half wave rectifier. With a 5 : 1 step down transformer, the minimum peak load voltage is closest to
a. 21 V
b. 25 V
c. 29.7 V
d. 35.4 V

Ans : c

18.The voltage out of a bridge rectifier is a
a. half wave signal
b. full wave signal
c. bridge rectified signal
d. sine wave

Ans : b

19.What is the peak load voltage in a full wave rectifier if the secondary voltage is 20 V rms?
a. 0 V
b. 0.7 V
c. 14.1 V
d. 28.3 V

Ans : c

20.We want a peak load voltage of 40 V out of a bridge rectifier. What is the approximate rms value of secondary voltage?
a. 0 V
b. 14.4 V
c. 28.3 V
d. 56.6 V

Ans : c

21.With a full wave rectified voltage across a load resistor, load current flows for what part of a cycle?
a. 0 degree
b. 90 degree
c. 180 degree
d. 360 degree

Ans : d

22.With the same secondary voltage and filter, which of the following has the most ripple?
a. half wave rectifier
b. full wave rectifier
c. bridge rectifier
d. impossible to say

Ans : a

23.With the same secondary voltage and filter which of the following produces the least load voltage?
a. half wave rectifier
b. full wave rectifier
c. bridge rectifier
d. impossible to say

Ans : a

24.If the filtered load current is 10 mA, which of the following has a diode current of 10 mA?
a. half wave rectifier
b. full wave rectifier
c. bridge rectifier
d. All above

Ans : d

25.The diodes in a bridge rectifier each have a maximum dc current rating of 2 A. this means the dc load current can have maximum value of
a. 1 A
b. 2 A
c. 4 A
d. 8 A

Ans : b

26.Efficiency of half wave rectifier is
a. 81.2 %
b. 40.6 %
c. 45.6 %
d. 82.1 %

Ans : b

27.Ripple factor of half wave rectifier is
a. 2.122
b. 1.112
c. 1.211
d. 2.11

Ans : c

28.Efficiency of full wave rectifier is
a. 81.2 %
b. 40.6 %
c. 45.6 %
d. 82.1 %

Ans : a

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

Ans : c

30.Efficiency of bridge rectifier is
a. 81.2 %
b. 40.6 %
c. 45.6 %
d. 82.1 %

Ans : a