Top 250+ Solved Power Electronics MCQ Questions Answer
Q. An IGBT has three terminals called:
a. Collector, Emitter and Base
b. Drain, Source and Base
c. Drain, Source and Gate
d. Collector, Emitter and Gate
Q. The function of snubber circuit connected across the SCR is to:
a. Suppress dv/dt
b. Increase dv/dt
c. Decrease dv/dt
d. Decrease di/dt
Q. An UJT exhibits negative resistance region:
a. Before the break point
b. Between peak and valley point
c. After the valley point
d. Both (a) and (c)
Q. For dynamic equalizing circuit used for series connected SCRs, thechoice of C is based on:
a. Reverse recovery characteristics
b. Turn-on characteristics
c. Turn-off characteristics
d. Rise time characteristics
Q. A four quadrant operation require:
a. Two full converters in series
b. Two full converters connected back to back
c. Two full converters connected in parallel
d. Two semi conductors connected back to back
Q. In a circulating-current type of dual converter, the nature of thevoltage across the reactor is:
a. Alternating
b. Pulsating
c. Direct
d. Triangular
Q. The frequency of the ripple in the output voltage of 3-phase semiconductor depends on:
a. Firing angle and load resistance
b. Firing angle and load inductance
c. The load circuit parameters
d. Firing angle and the supply frequency
Q. A single-phase full bridge inverter can operate in load-commutation mode in case load consists of:
a. RL load
b. RLC underdamped
c. RLC damped
d. RLC critically damped
Q. Practical way of obtaining static voltage equalization in series connected SCRs is by the use of:
a. One resistor across the string
b. Resistors of different values across each SCR
c. Resistors of the same value across each SCR
d. One resistor in series with each SCR
Q. A resistor connected across the gate and cathode of an SCR in acircuit increases its
a. dv/dt rating
b. Holding current
c. Noise Immunity
d. Turn-off time
Q. In thyristor, holding current is:
a. more than the latching current
b. less than the latching current
c. equal to latching current
d. none of the above
Q. When a thyristor turn on, the gate drive:
a. can be turned down but thyristor remains in on position
b. cannot be turned down as thyristor will be turned off
c. gate drive has no impact on starting and turning off the thyristor
d. none of the above
Q. A thyristor can be termed as:
a. DC switch
b. AC switch
c. both AC and DC switch
d. none of the above
Q. During forward blocking state, a thyristor is associated with:
a. large current and low voltage
b. low current and large voltage
c. medium current and large voltage
d. None of the above
Q. Turn-off time of an SCR is measured from the instant:
a. anode current becomes zero
b. anode voltage becomes zero
c. anode voltage and anode current becomes zero
d. gate current becomes zero