Explore topic-wise MCQs in Power Electronics.

This section includes 29 Mcqs, each offering curated multiple-choice questions to sharpen your Power Electronics knowledge and support exam preparation. Choose a topic below to get started.

1.

In a 1-phase full wave bridge rectifier with M-2 type of connection has secondary side voltage Vs = Vm sin ωt, with R load & ideal diodes.The expression for the average value of the output voltage can be given by

A. 2Vm/π
B. Vm/π
C. Vm/√2
D. 2Vm/√2
Answer» B. Vm/π
Discussion
2.

For a single phase half wave rectifier, the rectifier efficiency is always constant & it is

A. 4/π2
B. 8/π2
C. 100
D. 2/π2
Answer» B. 8/π2
Discussion
3.

Find the average value of output current for a 1-phase HW diode rectifier with R load, having RMS output current = 100A.

A. 200R A
B. 100/R√2 A
C. 200/R√2 A
D. 200/Rπ A
Answer» E.
Discussion
4.

A step-down delta-star transformer, with per-phase turns ratio of 5 is fed from a 3-phase 1100 V source. The secondary of this transformer is connected through a 3-pulse type rectifier, which is feeding an R load.The power delivered to the load is 6839.3 Watts.The maximum value of the load current is √2 x 22 A.Fin, the rms value of output voltage Vo (rms)

A. 257.3 V
B. 220 V
C. 261.52 V
D. 248.32 V
Answer» D. 248.32 V
Discussion
5.

The current ripple factor (CRF) is the ratio of

A. Average value/RMS value
B. RMS value/Average value
C. Average value/Maximum value
D. Maximum value/RMS value
Answer» C. Average value/Maximum value
Discussion
6.

In a 1-phase full wave bridge rectifier with M-2 type of connection has secondary side voltage Vs = Vm sin ωt,with R load & ideal diodes.The expression for the rms value of the output voltage can be given by

A. Vm/π
B. Vm/√2
C. Vm
D. Vm2
Answer» C. Vm
Discussion
7.

In case of an L filter, the ripple current increases with

A. increase in Load
B. decrease in Load
C. increase in the value of L
D. ripple current never increases
Answer» C. increase in the value of L
Discussion
8.

A single-phase diode B-2 rectifier is fed from a 250 V, 50 Hz source & connected to a load of R = 400 Ω.Design a capacitor filter such that the ripple factor of the output voltage is less than 5 %. Find the value of the capacitance of the C filter.

A. 156.4 μF
B. 500 μF
C. 189 μF
D. 246 μF
Answer» D. 246 μF
Discussion
9.

A load of R = 60 Ω is fed from 1phase, 230 V, 50 Hz supply through a step-up transformer & than a diode. The transformer turns ratio = 2. The power delivered to the load is

A. 614 Watts
B. 714 Watts
C. 814 Watts
D. 914 Watts
Answer» C. 814 Watts
Discussion
10.

A 3-phase bridge rectifier, has the average output voltage as 286.48 V. Find the maximum value of line voltage

A. 100 V
B. 200 V
C. 300 V
D. 400 V
Answer» D. 400 V
Discussion
11.

A 3-phase bridge rectifier charges a 240 V battery. The rectifier is given a 3-phase, 230 V supply. The current limiting resistance in series with the battery is of 8 Ω.Find the average value of battery charging current.

A. 12.56 A
B. 8.82 A
C. 9.69 A
D. 6.54 A
Answer» C. 9.69 A
Discussion
12.

A step-down delta-star transformer, with per-phase turns ratio of 5 is fed from a 3-phase 1100 V, 50 Hz source. The secondary of this transformer is connected through a 3-pulse type rectifier, which is feeding feeding an R load. Find the average value of output voltage.

A. 220 V
B. 257 V
C. 1100/√3 V
D. 206 V
Answer» C. 1100/√3 V
Discussion
13.

In a 1-Phase HW diode rectifier with R load, the average value of load current is given byTake Input (Vs) = Vm sinωt

A. Vm/R
B. Vm/2R
C. Vm/πR
D. Zero
Answer» D. Zero
Discussion
14.

For a single phase, full bridge, diode rectifier excited from a 230 V, 50 Hz source. With R = 10 Ω & the inductance(L) large enough to maintain continues conduction, the average and rms values of diode currents will be

A. 7.85 A, 8 A
B. 10.35 A, 7.85 A
C. 10.35 A, 14.6 A
D. 8 A, 8 A
Answer» D. 8 A, 8 A
Discussion
15.

The average value of the output voltage, in a 3-phase half wave diode rectifier with Vml as the maximum line voltage value, is given by the expression

A. Vml/3π
B. 2Vml/3π
C. 3Vml/2π
D. 3Vml
Answer» D. 3Vml
Discussion
16.

A diode rectifier with a C filter will have average output voltage _______ than that obtained by a rectifier without the C filter.

A. lower than
B. higher than
C. same as
D. none of the mentioned
Answer» C. same as
Discussion
17.

C filters are suitable for ___________ load resistances and L filters are suitable for _____________ load resistances.

A. low, low
B. high, high
C. high, low
D. low, high
Answer» D. low, high
Discussion
18.

An inductor filter connected in series with a resistive load provides a

A. smoothing of the output voltage waveform
B. smoothing of the input voltage waveform
C. smoothing of the output current waveform
D. smoothing of the input current waveform
Answer» D. smoothing of the input current waveform
Discussion
19.

In case of a C filter, if R (load resistance) is increased

A. ripple factor is reduced
B. ripple factor is increased
C. ripple factor is not affected
D. increases noise in the circuit
Answer» B. ripple factor is increased
Discussion
20.

An LC filter will have ripple factor value___________ (For the same value of L & C)

A. lower than that obtained by L filter but higher than that obtained by C filter
B. lower than that obtained by C filter but higher than that obtained by L filter
C. lower than that obtained by either L or C filter
D. higher than that obtained by either L or C filter
Answer» D. higher than that obtained by either L or C filter
Discussion
21.

In a single-phase full wave rectifier ___________ order harmonics are the most dominant

A. first
B. second
C. third
D. fourth
Answer» C. third
Discussion
22.

The PIV experienced by the diodes in the mid-point type configuration is

A. Vm
B. 2Vm
C. 4Vm
D. Vm/2
Answer» C. 4Vm
Discussion
23.

A 1-phase half wave diode rectifier with R = 1 KΩ, has input voltage of 240 V. The diode peak current is

A. Zero
B. 240mA
C. 24mA
D. 0.24mA
Answer» C. 24mA
Discussion
24.

For a single phase, full bridge, diode rectifier excited from a 230 V, 50 Hz source. With R = 10 Ω & the inductance(L) large enough to maintain continuous conduction, the value of the supply power factor will be

A. 0.707 lag
B. 0.9 lag
C. 0.86 lag
D. Unity
Answer» C. 0.86 lag
Discussion
25.

For a 3-phase 6-pulse diode rectifier, has Vml as the maximum line voltage value on R load. The peak current through each diode is

A. Vml/2R
B. 2Vml/R
C. Vml/R
D. Insufficient Data
Answer» D. Insufficient Data
Discussion
26.

A 3-phase bridge rectifier charges a 240-V battery. The rectifier is given a 3-phase 230 V supply. The current limiting resistance in series with the battery is 8 Ω.Find the power delivered to the battery (Pdc).

A. Pdc = 2000 W
B. Pdc = 1226 W
C. Pdc = 2356 W
D. Pdc = 2116 W
Answer» E.
Discussion
27.

For a certain diode based rectifier, the output voltage (average value) is given by the equation1/2π [ ∫Vm sin ωt d(ωt) ]Where the integral runs from 0 to πThe rectifier configuration must be that of a

A. single phase full wave with R load
B. single phase full wave with RL load
C. single phase half wave with R load
D. single phase half wave with RL load
Answer» D. single phase half wave with RL load
Discussion
28.

For a single phase half wave rectifier, with R load, the diode is reversed biased from ωt =

A. 0 to π, 2π to 2π/3
B. π to 2π, 2π/3 to 3π
C. π to 2π, 2π to 2π/3
D. 0 to π, π to 2π
Answer» C. π to 2π, 2π to 2π/3
Discussion
29.

The rectification efficiency for B-2 type & M-2 type full wave diode rectifiers are ___ & ___ respectively.

A. 8/π & 4/π
B. 4/π & 8/π
C. 8/π & 8/π
D. 4/π & 4/π
Answer» D. 4/π & 4/π
Discussion