Thyristors Questions and Answers

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Showing 10 of 24 questions
Q11
Which of the following devices might best be used to control an electric motor?
  • A an SCS
  • B a PUT
  • C an SCR
  • D a diac
Answer: Option C
Q12
You have a light-dimmer circuit using an SCR. In testing the circuit, you find that IG = 0 mA and the light is still on. You conclude that the trouble might be one of the following:
  • A the SCR is open.
  • B the switch is faulty.
  • C the gate circuit is shorted.
  • D this is normal; nothing is wrong.
Answer: Option D
Q13
How many semiconductor layers are thyristors constructed with?
  • A 2
  • B 3
  • C 4
  • D 5
Answer: Option C
Q14
Your boss has asked you to recommend a thyristor that will enable you to turn it on with a pulse and also turn it off with a pulse. Which of the following should you recommend?
  • A an SCR
  • B an SCS
  • C a PUT
  • D a triac
Answer: Option B
Q15
An SCR acts to control the speed of an electric motor by ________ the ________ of the pulse delivered to the motor.
  • A varying, width
  • B increasing, amplitude
  • C decreasing, gate width
  • D none of these
Answer: Option A
Q16
The anode-to-gate voltage can be used to turn the PUT on or off.
  • A TRUE
  • B FALSE
Answer: Option A
Q17
In an SCR-based half-wave phase-control circuit, a diode is connected in series with the anode.
  • A TRUE
  • B FALSE
Answer: Option B
Q18
The SCS is turned on with the cathode gate, and turned off with the anode gate.
  • A TRUE
  • B FALSE
Answer: Option B
Q19
UJTs can only be used to trigger triacs, not SCRs.
  • A TRUE
  • B FALSE
Answer: Option B
Q20
The SCR is a device that can be triggered off by a pulse applied to the gate.
  • A TRUE
  • B FALSE
Answer: Option B

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