Explore topic-wise MCQs in Electrical Engineering Questions.

This section includes 40 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.

Which of these is the best description for a Zener diode ?
A. It is a diode
B. It is a constant current device
C. It is a constant-voltage device
D. It works in the forward region
Answer» D. It works in the forward region
Discussion
2.

Another name for Zener diode is ______________diode?
A. Breakdown
B. Voltage
C. Power
D. Current
Answer» B. Voltage
Discussion
3.

In a loaded Zener regulator, which is the largest Zener current ?
A. Series current
B. Zener current
C. Load current
D. None of the above
Answer» B. Zener current
Discussion
4.

If the load resistance decreases in a Zener regulator, then Zener current ______________?
A. Decreases
B. Stays the same
C. Increases
D. None of the above
Answer» B. Stays the same
Discussion
5.

Commercial power supplies have voltage regulation ______________?
A. of 10%
B. of 15%
C. of 25%
D. within 1%
Answer» E.
Discussion
6.

In a regulated power supply, two similar 15 V zeners are connected in series. The input voltage is 45 V d.c. If each Zener has a maximum current rating of 300 mA, what should be the value of the series resistance ?
A. 10 O
B. 50 O
C. 25 O
D. 40 O
Answer» C. 25 O
Discussion
7.

A power supply can deliver a maximum rated current of 0.5 A at full-load output voltage of 20 V. What is the minimum load resistance that you can connect across the supply?
A. 10 O
B. 20 O
C. 15 O
D. 40 O
Answer» E.
Discussion
8.

A power supply has a voltage regulation of 1%. If the no-load voltage is 20 V, what is the full-load voltage ?
A. 8 V
B. 7 V
C. 6 V
D. 2 V
Answer» B. 7 V
Discussion
9.

A Zener voltage regulator will cease to act as a voltage regulator if Zener current becomes______________?
A. Less than load current
B. Zero
C. More than load current
D. None of the above
Answer» C. More than load current
Discussion
10.

A Zener regulator _____________ in the power supply?
A. Increases the ripple
B. Decreases the ripple
C. Neither increases nor decreases the ripple
D. Data insufficient
Answer» C. Neither increases nor decreases the ripple
Discussion
11.

A Zener diode that has very narrow depletion layer will breakdown by____________ mechanism?
A. Avalanche
B. Zener
C. Both avalanche and Zener
D. None of the above
Answer» C. Both avalanche and Zener
Discussion
12.

A 30 V Zener will have depletion layer width_______________ that of 10 V Zener?
A. More than
B. Less than
C. Equal to
D. None of the above
Answer» B. Less than
Discussion
13.

A Zener voltage regulator is used for ____________ load currents?
A. High
B. Very high
C. Moderate
D. Small
Answer» E.
Discussion
14.

For increasing the voltage rating, zeners are connected in_____________?
A. Parallel
B. Series-parallel
C. Series
D. None of the above
Answer» D. None of the above
Discussion
15.

In a Zener voltage regulator, the changes in load current produce changes in _________________?
A. Zener current
B. Zener voltage
C. Zener voltage as well as Zener current
D. None of the above
Answer» B. Zener voltage
Discussion
16.

Zener diode are generally made of _____________?
A. Germanium
B. Silicon
C. Carbon
D. None of the above
Answer» C. Carbon
Discussion
17.

If the doping level is increased, the breakdown voltage of the Zener_______________?
A. Remains the same
B. Is increased
C. Is decreased
D. None of the above
Answer» D. None of the above
Discussion
18.

As the junction temperature increases, the voltage breakdown point for avalanche mechanism______________?
A. Remains the same
B. Decrease
C. Increases
D. None of the above
Answer» D. None of the above
Discussion
19.

If the load current drawn by unregulated power supply increases, the d.c. output voltage______________?
A. Increases
B. Decreases
C. Stays the same
D. None of the above
Answer» C. Stays the same
Discussion
20.

A 5 mA changes in Zener current produces a 50 mA change in Zener voltage. What is the Zener impedance ?
A. 1 O
B. 1 O
C. 100 O
D. 10 O
Answer» E.
Discussion
21.

A Zener diode______________?
A. Is a battery
B. Acts like a battery in the breakdown region
C. Has a barrier potential of 1 V
D. Is forward biased
Answer» C. Has a barrier potential of 1 V
Discussion
22.

What is true about the breakdown voltage in a Zener diode ?
A. It decreases when load current increases
B. It destroys the diode
C. It equals current times the resistance
D. It is approximately constant
Answer» E.
Discussion
23.

A certain regulator has a no-load voltage of 6 V and a full-load output of 5.82 V. What is the load regulation ?
A. 09%
B. 87 %
C. 72 %
D. None of the above
Answer» B. 87 %
Discussion
24.

The current in a Zener diode is limited by _______________?
A. External resistance
B. Power dissipation
C. Both (A) and (B)
D. None of the above
Answer» D. None of the above
Discussion
25.

A Zener diode is used as a _____________voltage regulating device?
A. Shunt
B. Series
C. Series-shunt
D. None of the above
Answer» B. Series
Discussion
26.

If the load current drawn by unregulated power supply increases, the d.c. output voltage _____________?
A. Increases
B. Decreases
C. Stays the same
D. None of the above
Answer» C. Stays the same
Discussion
27.

Two similar 15 V Zeners are connected in series. What is the regulated output voltage ?
A. 15 V
B. 5 V
C. 30 V
D. 45 V
Answer» D. 45 V
Discussion
28.

When load current is zero, the Zener current will be_____________?
A. Zero
B. Minimum
C. Maximum
D. None of the above
Answer» D. None of the above
Discussion
29.

The Zener current will be minimum when_____________?
A. Load current is maximum
B. Load current is minimum
C. Load current is zero
D. None of the above
Answer» B. Load current is minimum
Discussion
30.

The load voltage is approximately constant when a Zener diode is ________________?
A. Forward biased
B. Unbiased
C. Reverse biased
D. Operating in the breakdown region
Answer» E.
Discussion
31.

If the input a.c. voltage to regulated or ordinary power supply increases by 5% what will be the approximate change in d.c. output voltage?
A. 10%
B. 20%
C. 15%
D. 5%
Answer» E.
Discussion
32.

A Zener diode utilises_____________characteristic for voltage regulation?
A. Forward
B. Reverse
C. Both forward and reverse
D. None of the above
Answer» C. Both forward and reverse
Discussion
33.

In an unregulated power supply, if input a.c. voltage increases, the output voltage _______________?
A. Increases
B. Decreases
C. Remains the same
D. None of the above
Answer» B. Decreases
Discussion
34.

As the junction temperature increases, the voltage breakdown point for Zener mechanism _______________?
A. Is increased
B. Is decreased
C. Remains the same
D. None of the above
Answer» C. Remains the same
Discussion
35.

In a 15 V Zener diode , the breakdown mechanism will occur by ______________?
A. Avalanche mechanism
B. Zener mechanism
C. Both Zener and avalanche mechanism
D. None of the above
Answer» B. Zener mechanism
Discussion
36.

In an unregulated power supply, if load current increases, the output voltage _____________?
A. Remains the same
B. Decreases
C. Increases
D. None of the above
Answer» C. Increases
Discussion
37.

The rupture of co-valent bonds will occur when the electric field is__________________?
A. 100 V/cm
B. 6 V/cm
C. 1000 V/cm
D. More than 105 V/cm
Answer» E.
Discussion
38.

An ideal regulated power supply is one which has voltage regulation of________________?
A. 0%
B. 5%
C. 10%
D. 1%
Answer» B. 5%
Discussion
39.

A power supply which has voltage regulation of ____________ is unregulated power supply?
A. 0 %
B. 5 %
C. 10 %
D. 8%
Answer» D. 8%
Discussion
40.

Zener diode can be used as__________________?
A. ac. voltage regulator only
B. dc. voltage regulator only
C. both D.C and A.C voltage regulator
D. none of the above
Answer» D. none of the above
Discussion