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เพาเวอร์ อิเล็กทรอนิคส์

Total questions: 36

Worksheet time: 48mins

Name
Class
Date
1.

Fill in the blank . Power Electronics  circuits involve______________ from one form to another using power semiconductor devices 

a)
converting mechanical power
b)
transfer heat
c)
converting electrical power
d)
converting electromagnetic field
2.

The controlling parameter in MOSFET is the......

a)
IG
b)
VGS
c)
ID
d)
VGE
3.

Which of the following statement is correct for an SCR operating in REVERSE BLOCKING MODE - practical condition

a)
leakage current flows from anode to cathode
b)
no leakage current
c)
leakage current flows from cathode to gate
d)
leakage current flows from cathode to anode
4.

Three types of common  power transistor are.....

a)
Diode, Triac and IGBT
b)
BJT, MOSFET and IGBT
c)
Diode, IGBT and GTO
d)
GTO, MOSFET and IGBT
5.

A single-phase half-wave type diode rectifier requires __________ number of diode(s) whereas full wave type requires _________ number of diode(s)

a)
4, 1
b)
1, 4
c)
1, 3
d)
3, 4
6.

For a certain diode based rectifier, the output voltage (average value) is given by the equation 1/2π ∫Vm sin (ωt) dωt ; where the integral (∫) runs from 0 to π. The rectifier configuration must be that of a....

a)
single phase controlled full wave with R load
b)
single phase uncontrolled full wave with R load
c)
single phase uncontrolled half wave with RL load
d)
single phase uncontrolled half wave with R load
7.
[5 minutes] A single-phase full wave rectifier is a..... (2 marks)
a)
multiple pulse rectifier
b)
single pulse rectifier
c)
two pulse rectifier
d)
three pulse rectifier
8.

With respect to the given circuit, from ωt = 0 to α, thyristors _____________ block the forward voltage.

a)
T1, T2
b)
T3, T4
c)
T1, T3
d)
T2, T4
9.

Choppers is..................converter

a)

AC -DC

b)

DC-AC

c)

AC-AC

d)

DC-DC

10.

A chopper may be thought as a

a)

Inverted with DC input

b)

DC equivalent of an AC transformer

c)

Diode rectifier

d)

DC equivalent of an induction motor

11.

Which device can be used in a chopper circuit?

a)

BJT

b)

MOSFET

c)

GTO

d)

ALL THE ABOVE

12.

What is the duty cycle of a chopper ?

a)

Ton/Toff

b)

Ton/T

c)

T/Ton

d)

Toff x Ton

13.

The load voltage of a chopper can be controlled by varying the..................

a)

duty cycle

b)

firing angle

c)

reactor position

d)

extinction angle

14.

Choose the correct statement:

a)

MOSFET is an uncontrolled device

b)

MOSFET is an voltage controlled device

c)

MOSFET is a current controlled device

d)

MOSFET is a temperature controlled device

15.

Which of the following terminals does NOT belong to a MOSFET.

a)

Base

b)

Gate

c)

Source

d)

Drain

16.

SCR is a:

a)

PNP device

b)

NPN device

c)

PN device

d)

PNPN device

17.

An SCR is a:

a)

four layer-three junction device

b)

three layer-two junction device

c)

four layer-four junction device

d)

three layer-three junction device

18.

TRIAC can be represented by:

a)

Two SCRs in anti-parallel

b)

Two SCRs in parallel

c)

Two diodes in anti-parallel

d)

Two diodes in parallel

19.

A DIAC can be represented by:

a)

Two diodes in anti-parallel

b)

Two diodes in parallel

c)

Two SCRs in anti-parallel

d)

Two SCRs in parallel

20.

MOSFET is:

a)

unipolar, voltage controlled two terminal device

b)

unipolar, voltage controlled, three terminal device

c)

bipolar, voltage controlled two terminal device

d)

bipolar, voltage controlled, three terminal device

21.

Which among the following is suited for high frequency applications:

a)

MOSFET

b)

JFET

c)

SCR

d)

TRIAC

22.

JFET has high input impedance because

a)

the input region is reverse biased

b)

the input region is heavily doped

23.

What is the full form of IGBT...?

a)

Insulation gate bipolar transistor

b)

Insulation gate bidirectional transistor

c)

Insulated gate bipolar transistor

d)

Insulated gate bidirectional transistor

24.
For an SCR in the forward blocking mode (practically)
a)
leakage current does not flow
b)
leakage current flows from anode to cathode
c)
leakage current flows from cathode to anode
d)
leakage current flows from gate to anode
25.

Which of the following devices should be used as a switch in a low power switched mode power supply (SMPS)?

a)

GTO

b)

MOSFET

c)

TRIAC

d)

SCR

26.

Power converters can change one form of power to another form of power using semiconductor power devices.

a)

True

b)

False

27.

If holding current of a thyristor is 2 mA then latching current should be____

a)

0.02

b)

0.001

c)

0.004

d)

0.002

28.
For an SCR in the forward blocking mode (practically)
a)
leakage current does not flow
b)
leakage current flows from anode to cathode
c)
leakage current flows from cathode to anode
d)
leakage current flows from gate to anode
29.

Diode pass ......... in one direction?

a)

a) Voltage

b)

b) Current

c)

c) Both

d)

d) None of these

30.

The electronic devices below are unidirectional devices EXCEPT:

a)

TRIAC

b)

Diode

c)

Silicone Controlled Rectifier

31.

Power Electronics can be defined as ...........

a)

A conversion from Alternating Current to Direct Current of Power Supply

b)

A conversion of DC power supply to AC power supply

c)

A conversion of AC power supply to AC power supply

d)

A technology of converting electric power from one supply to another supply using electronic power devices.

32.

Which is the symbol of SCR?

a)
b)
c)
d)
33.

To switch on BJT, current must be applied into terminal ................... of BJT

a)

Collector

b)

Emitter

c)

Gate

d)

Base

34.
Identify the Converter type?
a)
1Φ Dual Converter
b)
3Φ Single Converter
c)
3Φ Dual Converter
d)
1Φ Single Converter
35.
A fully controlled converter uses
a)
 diodes only
b)
 thyristors only
c)
 both diodes and thyristors
d)
Noe of them
36.
dv/dt protection is provided to the SCR by
a)
connecting a capacitor in parallel with the load
b)
connecting an inductor in series with the load
c)
connecting a capacitor & resister in parallel with the device
d)
connecting an inductor & resister in parallel with the device