Power Electronics MCQ Multiple Choice Questions - Page 6 for Practice

Q: 76. A triac can pass a portion of …………… half-cycle through the load

Correct Answer is: Both positive and negative

Q: 78. A Triac has three terminals viz ………………

Correct Answer is: Two main terminal and a gate terminal

Q: 79. A triac is a …………. switch

Correct Answer is: Bidirectional

Q: 80. A triac is equivalent to two SCRs …………..

Correct Answer is: In inverse-parallel

Q: 81. A UJT has ……………….

Correct Answer is: One pn junction

Q: 83. AC power in a load can be controlled by using

Correct Answer is: two SCRs in parallel opposition

Q: 84. After peak point, the UJT operates in the ……………. region

Correct Answer is: Negative resistance

Q: 85. An SCR can be used

Correct Answer is: all of these

Q: 86. An SCR is made up of silicon because

Correct Answer is: silicon has small leakage current than germanium

Q: 87. Between the incoming and outgoing devices in voltage commutation

Correct Answer is: No overlapping operation

Power Electronics MCQ Questions for Practice

76. A triac can pass a portion of …………… half-cycle through the load

Only negative
Both positive and negative
Only positive
None of the above

77. A triac has …………….. semiconductor layers

Three
Four
Two
Five

78. A Triac has three terminals viz ………………

Two main terminal and a gate terminal
Cathode, anode, gate
Drain, source, gate
None of the above

79. A triac is a …………. switch

Unidirectional
Mechanical
Bidirectional
None of the above

80. A triac is equivalent to two SCRs …………..

In series
In inverse-parallel
In parallel
None of the above

81. A UJT has ……………….

One pn junction
Three pn junctions
Two pn junctions
None of the above

82. A UJT is sometimes called …………. diode

High resistance
Single-base
Low resistance
Double-base

83. AC power in a load can be controlled by using

two SCRs in series
three SCRs in series
two SCRs in parallel opposition
four SCRs in series

84. After peak point, the UJT operates in the ……………. region

Saturation
Negative resistance
Cut-off
None of the above

85. An SCR can be used

for power control
for speed control of dc shunt motor
as static conductor
all of these

86. An SCR is made up of silicon because

silicon has small leakage current than germanium
silicon has small leakage voltage than germanium
silicon has large leakage current than germanium
silicon has large leakage voltage than germanium

87. Between the incoming and outgoing devices in voltage commutation

Small overlapping operation
No overlapping operation
Large overlapping takes place
None of these

88. Between the peak point and the valley point of UJT emitter characteristics we have ………….. region

Negative resistance
Cut-off
Saturation
None of the above

89. Double fourier series analysis of PWM is

Three dimensional functions
One dimensional functions
Two dimensional functions
All of these

90. During the commutation period in 3 phase converter, overlap time is

Dependent on the voltage
Dependent on both the load current and load voltage behind the short circuit current
Dependent on the load current
Independent on both the load current and load voltage