Top 250+ Solved Power Electronics MCQ Questions Answer
Q. Least undulating current will be delivered by which mercury arc rectifier
a. 1-phase
b. 2 phase
c. 3 phase
d. 6 phase.
Q. In a mercury arc rectifier the cathode voltage drop is due to
a. surface resistance
b. expenditure of energy in liberating electrons from the mercury
c. expenditure of energy in ionization
d. expenditure of energy in overcoming the electrostatic fiel
Q. In mercury arc rectifier, voltage drop at anode is due to
a. energy spent in overcoming the electrostatic field
b. high temperature inside the rectifier
c. self-restoring property of mercury
d. high ionization potential.
Q. The average life of the glass bulb rectifier is
a. 100 to 150 hours
b. 1000 to 1500 hours
c. 10,000 to 15,000 hours
d. 100,000 to 150,000 hours.
Q. The vacuum inside the glass bulb of a mercury arc rectifier is of the order of
a. 5 x 10-3 cm of Hg
b. 5 x 10-4 cm of Hg
c. 5 x 10-5 cm of Hg
d. 5 x 10-8 cm of Hg.
Q. For mercury arc rectifiers, the anode is usually made of
a. Aluminium
b. Copper
c. Tungsten
d. Graphite.
Q. The maximum firing angle in the half wave controlled regulator is
a. 180 degree
b. 190 degree
c. 200 degree
d. 210 degree
Q. The on - state voltage drop of IGBT consists of
a. Drop across the collector junction
b. Drop across the drift region
c. Drop across MOSFET portion
d. All of these
Q. To detect an over - current fault condition, the most reliable method is toconnect a
a. Current sensor across IGBT
b. Voltage sensor across IGBT
c. Current sensor in series with IGBT
d. Voltage sensor in series with IGBT
Q. The IGBT resulted in higher switching speed and lower energy losses. It canbe used for
a. Uninterruptible power supplies
b. Induction heating system
c. Constant voltage and frequency power supplies
d. All of these
Q. An ideal diode is
a. Unidirectional
b. Bidirectional
c. Fixed voltage polarity
d. Only (a) and (c)
Q. With gate open, the maximum anode current at which SCR is turned offfrom ON condition is called
a. breakdown voltage
b. peak reverse voltage
c. holding current
d. latching current
Q. The curve between V and I of SCR when anode is positive w.r.t cathode andwhen anode is negative w.r.t cathode are known as
a. both as forward characteristics
b. both as reverse characteristics
c. former as forward characteristics and later as reverse characteristics
d. former as reverse characteristics and later as forward characteristics