Top 250+ Solved Power Electronics MCQ Questions Answer
Q. A static induction thyristor
a. is a majority carrier device
b. is a minority carrier device
c. either a majority carrier or minority carrier device
d. has a total number of 2 leads
Q. A single phase step up cycloconverter changes 50 Hz to 100 Hz.Then one half wave of input will give rise to
a. one half wave of output
b. one full wave of output
c. two full waves of output
d. either (b) or (c)
Q. Which of these triggering methods for series connected SCRs use LASCR in the gate circuit?
a. Resistance triggering
b. Simultaneous triggering
c. Sequential triggering
d. Optical triggering
Q. The average load current supplied by a thyristor depends on
a. firing angle
b. firing frequency
c. magnitude of gate current
d. all of the above
Q. In a 3 phase full wave regulator feeding a star connected resistance load the input voltage is 400 V line to line. The firing angle is 160°. The line to line output voltage would be
a. 400 V
b. about 100 V
c. about 20 V
d. Zero
Q. A thyristor is reverse biased. A positive gate pulse is applied. Thethyristor
a. will be turned on
b. may or may not turn on
c. will not turn on
d. will turn on after sometime
Q. A single phase series converter is used for
a. high voltage output
b. high current output
c. high voltage and high current output
d. improving the circuit efficiency
Q. A single phase half wave controlled rectifier circuit has an R-L load.A freewheeling diode is also in the circuit. When freewheeling diode is conducting the SCR
a. is forward biased
b. is reverse biased
c. may be forward biased or reverse biased
d. forward biased initially but reverse biased afterwards
Q. In 180° mode of operation of a 3 phase bridge inverter, two thyristors conduct at one time.
a. True
b. False
c. none
d. all
Q. A reactor is used in a dual converter operating in non-circulating current mode.
a. True
b. False
c. none
d. all
Q. Which of these commutation methods uses an auxiliary SCR?
a. Class A
b. Class B
c. Class C
d. Class D