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Electrical Engineering Mcqs

When a large surge current of very short duration flows through a thyristor then which one of the following device will operate to protect the thyristor ___________?

  • (A)  CB
  • (B)  Snubber circuit
  • (C)  Voltage clamping device
  • (D)  Fast acting current limiting device (FACL fuse)
Submitted By :Ali Uppal


A power semiconductor may undergo damage due to____________?

  • (A)  High di/dt
  • (B)  High dv/dt
  • (C)  Low di/dt
  • (D)  Low dv/dt
Submitted By :Ali Uppal


CB used for over current protection of thyristor operates when the fault current is__________?

  • (A)  of long period
  • (B)  of short duration
  • (C)  both (A) and (B)
  • (D)  neither (A) nor (B)
Submitted By :Ali Uppal


Submitted By :Ali Uppal


Submitted By :Ali Uppal


Materials used in heat sink should have_____________?

  • (A)  high thermal conductivity
  • (B)  large surface area
  • (C)  high melting point
  • (D)  All of these
Submitted By :Ali Uppal


A thyristor can termed as__________?

  • (A)  AC switch
  • (B)  DC switch
  • (C)  Both a and B
  • (D)  Square wave switch
Submitted By :Ali Uppal


Which of the following is used in heat sink_____________?

  • (A)  Iron
  • (B)  Aluminium
  • (C)  Carbon
  • (D)  Silver
Submitted By :Ali Uppal


How can we protect SCR from thermal conditions _____________?

  • (A)  Use of snubber circuit.
  • (B)  Using heat sink.
  • (C)  Using CB and fuse.
  • (D)  Using equalizing circuit
Submitted By :Ali Uppal


Thyristor is nothing but a____________?

  • (A)  Controlled transistor
  • (B)  Controlled switch
  • (C)  Amplifier with higher gain
  • (D)  Amplifier with large current gain
Submitted By :Ali Uppal