MCQ on Power Electronics & Drives

Rajasthan Polytechnic Third Year Paper 2016 – Power Electronics & Drives

Thyrister is
(a) controlled switch
(b) controlled transistor
(c) amplifier with high rating current
(d) high gain amplifier

In SCR, holding current is
(a) more than latching current
(b) less than latching current
(c) equal to latching current
(d) zero

UJT known as
(a) Voltage controlled device
(b) current controlled device
(c) relaxation oscillator
(d) none of above

The most appropriate method for pure triggring of SCR is
(a) Pulse control
(b) Bias control
(c) Phase shift control
(d) Bias phase shift control

SCR can be turned off from on condition
(a) zero gate current
(b) use of force-commutation
(c) zero gate voltage
(d) break junctions

The best firing method of SCR is
(a) By ‘R’
(b) By R-C
(c) By UJT
(d) By Pedestal Ramp

Output ripple factor of three phase half wave rectifier is
(a) 1.21
(b) 0.6
(c) 0.17
(d) 0.48

Which rectifier has minimum efficiency?
(a) 6 phase
(b) 3 phase half wave
(c) 1 phase full wave
(d) 3 phase bridge

The value of ripple factor of single phase half wave rectifier
(a) 1.57
(b) 1.21
(c) 1.11
(d) 0.482

A power chopper changed
(a) AC to DC
(b) DC to DC
(c) DC to AC
(d) None of all

Whichtype of commutatin used in Jone’s Chopper?
(a) Class A
(b) Class B
(c) Class C
(d) Class D

Inverter is instrument
(a) Change AC to DC
(b) Change AC to AC
(c) Change DC to DC
(d) Change DC to AC

Seires inverter gives
(a) sine wave
(b) square wave
(c) triangular wave
(d) saw tooth wave