Explore topic-wise MCQs in Electrical Engineering Questions.

This section includes 44 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.

1.

The maximum efficiency of a half-wave rectifier is _____________?
A. 40.6 %
B. 81.2 %
C. 50 %
D. 25 %
Answer» B. 81.2 %
Discussion
2.

A crystal diode has______________?
A. one pn junction
B. two pn junctions
C. three pn junctions
D. none of the above
Answer» B. two pn junctions
Discussion
3.

A 1,000 V power supply would use_____________ as a filter capacitor?
A. paper capacitor
B. air capacitor
C. mica capacitor
D. electrolytic capacitor
Answer» B. air capacitor
Discussion
4.

A zener diode has ________________?
A. one pn junction
B. two pn junctions
C. three pn junctions
D. none of the above
Answer» B. two pn junctions
Discussion
5.

If the a.c. input to a half-wave rectifier is an r.m.s value of 400/√2 volts, then diode PIV rating is__________________?
A. 400/√2 V
B. 400 V
C. 400 x √2 V
D. none of the above
Answer» C. 400 x √2 V
Discussion
6.

A zener diode utilizes ______________ characteristics for its operation?
A. forward
B. reverse
C. both forward and reverse
D. none of the above
Answer» C. both forward and reverse
Discussion
7.

There is a need of transformer for__________________?
A. half-wave rectifier
B. centre-tap full-wave rectifier
C. bridge full-wave rectifier
D. none of the above
Answer» C. bridge full-wave rectifier
Discussion
8.

The disadvantage of a half-wave rectifier is that the__________________?
A. components are expensive
B. diodes must have a higher power rating
C. output is difficult to filter
D. none of the above
Answer» D. none of the above
Discussion
9.

The doping level in a zener diode is______________ that of a crystal diode?
A. the same as
B. less than
C. more than
D. none of the above
Answer» D. none of the above
Discussion
10.

A zener diode has ______________ breakdown voltage?
A. undefined
B. sharp
C. zero
D. none of the above
Answer» C. zero
Discussion
11.

A zener diode is always_______________ connected?
A. reverse
B. forward
C. either reverse or forward
D. none of the above
Answer» B. forward
Discussion
12.

A zener diode is destroyed if it______________?
A. is forward biased
B. is reverse biased
C. carrier more than rated current
D. none of the above
Answer» D. none of the above
Discussion
13.

A crystal diode utilises …………….. characteristic for rectification
A. reverse
B. forward
C. forward or reverse
D. none of the above
Answer» C. forward or reverse
Discussion
14.

When a crystal diode is used as a rectifier, the most important consideration is ____________?
A. forward characteristic
B. doping level
C. reverse characteristic
D. PIC rating
Answer» E.
Discussion
15.

For the same secondary voltage, the output voltage from a centre-tap rectifier is___________ than that of bridge rectifier?
A. twice
B. thrice
C. four time
D. one-half
Answer» E.
Discussion
16.

The knee voltage of a crystal diode is approximately equal to ________________?
A. applied voltage
B. breakdown voltage
C. forward voltage
D. barrier potential
Answer» E.
Discussion
17.

A 10 V power supply would use ____________ as filter capacitor?
A. paper capacitor
B. mica capacitor
C. electrolytic capacitor
D. air capacitor
Answer» D. air capacitor
Discussion
18.

A zener diode is used as ______________?
A. an amplifier
B. a voltage regulator
C. a rectifier
D. a multivibrator
Answer» C. a rectifier
Discussion
19.

A half-wave rectifier has an input voltage of 240 V r.m.s. If the step-down transformer has a turns ratio of 8:1, what is the peak load voltage? Ignore diode drop?
A. 27.5 V
B. 86.5 V
C. 30 V
D. 42.5 V
Answer» E.
Discussion
20.

_____________ filter circuit results in the best voltage regulation?
A. choke input
B. capacitor input
C. resistance input
D. none of the above
Answer» B. capacitor input
Discussion
21.

The most widely used rectifier is ________________?
A. half-wave rectifier
B. centre-tap full-wave rectifier
C. bridge full-wave rectifier
D. none of the above
Answer» D. none of the above
Discussion
22.

If the PIV rating of a diode is exceeded,_______________?
A. the diode conducts poorly
B. the diode is destroyed
C. the diode behaves like a zener diode
D. none of the above
Answer» C. the diode behaves like a zener diode
Discussion
23.

The PIV rating of each diode in a bridge rectifier is ___________that of the equivalent center-tap rectifier?
A. one-half
B. the same as
C. twice
D. four times
Answer» B. the same as
Discussion
24.

A series resistance is connected in the zener circuit to_______________?
A. properly reverse bias the zener
B. protect the zener
C. properly forward bias the zener
D. none of the above
Answer» C. properly forward bias the zener
Discussion
25.

____________ rectifier has the lowest forward resistance?
A. solid state
B. vacuum tube
C. gas tube
D. none of the above
Answer» B. vacuum tube
Discussion
26.

When the crystal current diode current is large, the bias is ______________?
A. forward
B. inverse
C. poor
D. reverse
Answer» B. inverse
Discussion
27.

In the breakdown region, a zener didoe behaves like a _______________source?
A. constant voltage
B. constant current
C. constant resistance
D. none of the above
Answer» B. constant current
Discussion
28.

If the temperature of a crystal diode increases, then leakage current ______________?
A. remains the same
B. decreases
C. increases
D. becomes zero
Answer» D. becomes zero
Discussion
29.

A zener diode is________________ device?
A. a non-linear
B. a linear
C. an amplifying
D. none of the above
Answer» B. a linear
Discussion
30.

Mains a.c. power is converrted into d.c. power for_________________?
A. lighting purposes
B. heaters
C. using in electronic equipment
D. none of the above
Answer» D. none of the above
Discussion
31.

The ripple factor of a half-wave rectifier is_________________?
A. 2
B. 1.21
C. 2.5
D. 0.48
Answer» E.
Discussion
32.

The ratio of reverse resistance and forward resistance of a germanium crystal diode is about ______________?
A. 1 : 1
B. 100 : 1
C. 1000 : 1
D. 40,000 : 1
Answer» E.
Discussion
33.

If the doping level of a crystal diode is increased, the breakdown voltage__________________?
A. remains the same
B. is increased
C. is decreased
D. none of the above
Answer» D. none of the above
Discussion
34.

A crystal diode is used as______________?
A. an amplifier
B. a rectifier
C. an oscillator
D. a voltage regulator
Answer» C. an oscillator
Discussion
35.

A crystal diode has forward resistance of the order of ________________?
A. kΩ
B. Ω
C. MΩ
D. none of the above
Answer» C. MΩ
Discussion
36.

If the arrow of crystal diode symbol is positive w.r.t. bar, then diode is _____________biased?
A. forward
B. reverse
C. either forward or reverse
D. none of the above
Answer» B. reverse
Discussion
37.

The d.c. resistance of a crystal diode is ______________ its a.c. resistance?
A. the same as
B. more than
C. less than
D. none of the above
Answer» D. none of the above
Discussion
38.

The forward voltage drop across a silicon diode is about _______________?
A. 2.5 V
B. 3 V
C. 10 V
D. 0.7 V
Answer» E.
Discussion
39.

The reverse current in a diode is of the order of _____________?
A. kA
B. mA
C. μA
D. A
Answer» D. A
Discussion
40.

The leakage current in a crystal diode is due to _________________?
A. minority carriers
B. majority carriers
C. junction capacitance
D. none of the above
Answer» B. majority carriers
Discussion
41.

The PIV rating of a crystal diode is _______________ that of equivalent vacuum diode
A. the same as
B. lower than
C. more than
D. none of the above
Answer» C. more than
Discussion
42.

When the graph between current through and voltage across a device is a straight line, the device is referred to as _______________?
A. linear
B. active
C. nonlinear
D. passive
Answer» B. active
Discussion
43.

A crystal diode is a ________________device?
A. non-linear
B. bilateral
C. linear
D. none of the above
Answer» B. bilateral
Discussion
44.

If the doping level in a crystal diode is increased, the width of depletion layer_____________?
A. remains the same
B. is decreased
C. in increased
D. none of the above
Answer» D. none of the above
Discussion