MCQ On Power Electronics: Electrical Engineering MCQs

MCQ On Power Electronics. MCQs on the topic of Power Electronics

 

MCQ On Power Electronics

 

A Triac is a ?

A. 2 terminal switch
B. 2 terminal bilateral switch
C. 3 terminal bilateral switch
D. 3 terminal bidirectional switch

View Answer

D. 3 terminal bidirectional switch

 

A thyristor is basically ?

A. PNPN device
B. A combination of diac and triac
C. A set of SCRs
D. A set if SCR,diac and triac

View Answer

A. PNPN device

 

In reverse blocking mode of a thyristor ?

A. junction J2 is in reverse bias and J1, J3 is in forward bias
B. junction J3 is in forward bias and J1, J2 in reverse bias
C. junction J1, J3 is in reverse bias and J2 is in forward bias
D. junction J1 and J2 is in forward bias and J3 is in reverse bias

View Answer

C. junction J1, J3 is in reverse bias and J2 is in forward bias

 

The switching function of semiconductor devices can be characterized with ?

A. Duty ratio only
B. Frequency only
C. Duty ratio and frequency
D. Duty ratio, frequency and time delay

View Answer

D. Duty ratio, frequency and time delay

 

In forward blocking mode of a thyristor ?

A. junction J2 is in reverse bias and J1, J3 is in forward bias
B. junction J3 is in forward bias and J1, J2 is in reverse bias
C. Junction J1, J3 is in reverse bias and J2 is in forward bias
D. Junction J1 and J2 is in forward bias and J3 is in reverse bias

View Answer

A. junction J2 is in reverse bias and J1, J3 is in forward bias

 

A Triac has three terminals viz ?

A. Drain, source, gate
B. Two main terminal and a gate terminal
C. Cathode, anode, gate
D. None of the above

View Answer

B. Two main terminal and a gate terminal

 

MCQ On Power Electronics

 

Which of the following is used in heat sink ?

A. Iron
B. Aluminium
C. Carbon
D Silver

View Answer

B. Aluminium

 

An SCR is considered to be a semi controlled device because ?

A. it can be turned OFF but not ON with a gate pulse
B. it conducts only during one half cycle of an alternating current wave
C. it can be turned ON but not OFF with a gate pulse
D. it can be turned ON only during one half cycle of an AC

View Answer

C. it can be turned ON but not OFF with a gate pulse

 

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

A. 0.01 A
B. 0.002 A
C. 0.009 A
D. 0.004 A

View Answer

D. 0.004 A

 

A thyristor equivalent of a thyratron tube is a ?

A. Diac
B. Triac
C. Silicon controlled-rectifier SCR
D. None of above

View Answer

C. Silicon controlled-rectifier SCR

 

For bidirectional operation of converters ?

A. A parallel combination of controllable switch and a diode is used
B. A parallel combination of controllable switch and capacitor is used
C. A series combination of controllable switch and a diode is used
D. A series combination of controllable switch and a capacitor is used

View Answer

D. A series combination of controllable switch and a capacitor is used

 

In rectifiers, load current flow is ?

A. Unidirectional
B. Bidirectional
C. Either (a) or (b)
D. Non directional

View Answer

A. Unidirectional

 

MCQ On Power Electronics

 

In a 3 phase bridge rectifier the ripple frequency is ?

A. Equal to the input frequency
B. Twice the input frequency
C. Three times the input frequency
D. Six times the input frequency

View Answer

D. Six times the input frequency

 

In a load commutated DC – DC chopper, the capacitor has a ?

A. Symmetric triangular voltage across itself
B. Symmetric rectangular voltage across itself
C. Symmetric trapezoidal voltage across itself
D. Symmetric sinusoidal voltage across itself

View Answer

C. Symmetric trapezoidal voltage across itself

 

Thyristor is nothing but a ?

A. Controlled transistor
B. Controlled switch
C. Amplifier with higher gain
D. Amplifier with large current gain

View Answer

B. Controlled switch

 

Choppers is a ?

A. AC – DC converters
B. AC – AC converters
C. DC – AC converters
D. DC – DC converters

View Answer

D. DC – DC converters

 

AC power in a load can be controlled by using ?

A. Two SCR’s in parallel opposition
B. Two SCR’s in series
C. Three SCR’s in series
D. Four SCR’s in series

View Answer

A. Two SCR’s in parallel opposition

 

An SCR is made up of silicon because ?

A. silicon has large leakage current than germanium
B. silicon has small leakage current than germanium
C. silicon has small leakage voltage than germanium
D. silicon has large leakage voltage than germanium

View Answer

B. silicon has small leakage current than germanium

 

MCQ On Power Electronics

 

Unipolar modulation is generally used in ?

A. AC – AC converters
B. AC – DC converters
C. DC – AC converters
D. DC – DC converters

View Answer

D. DC – DC converters

 

A modern power semiconductor device that combines the characteristic of BJT and MOSFET is ?

A. IGBT
B. FCT
C. MCT
D. GTO

View Answer

A. IGBT

 

Snubber circuit is used with SCR ?

A. in series
B. in parallel
C. either series or parallel
D. anti parallel

View Answer

B. in parallel

 

Why resistor is used in Snubber circuit ?

A. To minimize the loss
B. To minimize the charging current
C. To minimize the discharging current
D. All of these

View Answer

C. To minimize the discharging current

 

Gate circuit or triggering circuit of a thyristor is ?

A. lower power circuit
B. high power circuit
C. magnetic circuit
D. may be low power or high power circuit

View Answer

A. lower power circuit

 

a thyristor can be termed as ?

A. AC switch
B. DC switch
C. Both a and B
D. Square wave switch

View Answer

B. DC switch

 

MCQ On Power Electronics

 

Which triggering is the most reliable ?

A. Forward voltage triggering
B. Gate triggering
C. dV / dt triggering
D. Thermal triggering

View Answer

B. Gate triggering

 

Thyristor can be protected from over voltages by using ?

A. voltage clamping device
B. fuse
C. heat sink
D. snubber circuit

View Answer

A. voltage clamping device

 

You can protect a Thyristor from over voltages by using ?

A. 23 mA
B. 40 mA
C. 10 mA
D. 60 mA

View Answer

C. 10 mA

 

What is used to protect the SCR from over current ?

A. CB and fuse
B. Heat sink
C. Snubber circuit
D. Voltage clamping device

View Answer

A. CB and fuse

 

Read More

Leave a Comment

Your email address will not be published. Required fields are marked *

error: Content is protected !!