Q.1
The UJT may be used as ___________.
  • Am amplifier
  • A sawtooth generator
  • A rectifier
  • None of the above
Q.2
The Gate-Drain transfer capacitance of a MOSFET has large value in the ________________ region and small value in the ________________ region.
  • saturation, ohmic
  • ohmic, saturation
  • triode, linear
  • ohmic, active
Q.3
A diac has ___________ semiconductor layers
  • Three
  • Two
  • Four
  • None of the above
Q.4
The device that does not have the gate terminal is ___________.
  • Triac
  • FET
  • SCR
  • Diac
Q.5
A single phase half wave controlled converter always operates in the ________ conduction mode.
  • continuous
  • discontinuous
  • both (a) and (b)
  • none of the above
Q.6
In case of three-phase dual converter, one of the converter circuits is fired at an angle of 60°. For both the converter circuits to have equal average output voltage, what is the value of the firing angle for the other converter circuit?
  • 60°
  • 120°
  • 100°
  • Insufficient data
Q.7
The process of commutating a SCR by applying a reverse voltage to an SCR through a previously charged capacitor is called as
  • capacitor commutation
  • forced commutation
  • voltage commutation
  • current commutation
Q.8
How does resistance affect current?
  • less resistance - less current
  • more resistance - less current
  • more resistance - more current
  • resistance does not affect current
Q.9
The normal way to turn on a diac is by ___________.
  • Gate current
  • Gate voltage
  • Breakover voltage
  • None of the above
Q.10
Circulating current flows
  • from load to converters
  • from one converter to another converter
  • in the whole circuit
  • none of the mentioned
Q.11
In non-circulating current mode dual converters, the circulating current is avoided by
  • connecting a series reactor
  • maintaining α1 + α2 = 180°
  • adding an extra SCR
  • operating only one converter
Q.12
In pulse width modulation scheme, _________ is kept constant
  • ton
  • toff
  • Fs
  • Ts
Q.13
A chopper may be thought as a
  • Inverted with DC input
  • DC equivalent of an AC transformer
  • Diode rectifier
  • DC equivalent of an induction motor
Q.14
In the principle of phase control
  • control is achieved by adjusting the firing angle of the devices
  • the load is on for some cycles and off for some cycles
  • control is achieved by adjusting the number of on off cycles
  • control cannot be achieved
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