Thyristors And Tranducers MCQs

Practice and Learn through MCQs and Quizzes. have 16 Thyristors And Tranducers MCQs

A transducer’s function is to:

  • A. transmit electrical energy
  • B. convert energy
  • C. produce mechanical energy
  • D. prevent current flow
  • Correct Answer: Option B


  • A. can trigger only on positive gate voltages
  • B. can trigger only on negative gate voltages
  • C. cannot be triggered with gate voltages
  • D. can be triggered by either a positive or a negative gate voltage
  • Correct Answer: Option D

A UJT has:

  • A. two base leads
  • B. one emitter lead
  • C. two emitter leads and one base lead
  • D. one emitter lead and two base leads
  • Correct Answer: Option D

An optically coupled isolator is a device containing _________ in a single package.

  • A. a photodiode and an optotransmitter
  • B. an LED and an SCR
  • C. an anode and a cathode
  • D. an IRED and a silicon phototransistor
  • Correct Answer: Option D

Once a DIAC is conducting, the only way to turn it off is with:

  • A. a positive gate voltage
  • B. a negative gate voltage
  • C. low-current dropout
  • D. breakover
  • Correct Answer: Option C

The DIAC is a:

  • A. transistor
  • B. unidirectional device
  • C. three-layer device
  • D. bidirectional device
  • Correct Answer: Option D

The only way to close an SCR is with:

  • A. a trigger input applied to the gate
  • B. forward breakover voltage
  • C. low-current dropout
  • D. valley voltage
  • Correct Answer: Option B

The PUT (programmable unijunction transistor) is actually a type of:

  • A. UJT thyristor
  • B. FET device
  • C. TRIAC
  • D. SCR
  • Correct Answer: Option A

The smallest amount of current that the cathode-anode can have, and still sustain conduction of an SCR is called the:

  • A. maximum forward current
  • B. maximum forward gate current
  • C. holding current
  • D. reverse gate leakage current
  • Correct Answer: Option D

The TRIAC is equivalent to ________________.

  • A. a four-layer diode
  • B. two DIACs in parallel
  • C. a thyristor with a gate lead
  • D. two SCRs in parallel
  • Correct Answer: Option D

What causes the piezoelectric effect?

  • A. heat or dissimilar metals
  • B. pressure on a crystal
  • C. water running on iron
  • D. a magnetic field
  • Correct Answer: Option B

What does a hall effect sensor sense?

  • A. temperature
  • B. moisture
  • C. magnetic fields
  • D. pressure
  • Correct Answer: Option C

What is an SCR?

  • A. a PNPN thyristor with 3 terminals
  • B. a PNPN thyristor with 4 terminals
  • C. a PNP thyristor with 3 terminals
  • D. an NPN thyristor with 3 terminals
  • Correct Answer: Option A

What type of application would use a photovoltaic cell?

  • A. an automobile horn
  • B. a TI 92 calculator
  • C. a magnetic field detector
  • D. a remote power source
  • Correct Answer: Option D

What type of application would use an injection laser diode?

  • A. a 10BASE-T Ethernet
  • B. a liquid crystal display
  • C. a fiber optic transmission line
  • D. a good flashlight
  • Correct Answer: Option C

When checking a good SCR or TRIAC with an ohmmeter it will:

  • A. show high resistance in both directions
  • B. show low resistance with positive on anode and negative on cathode, and high resistance when reversed
  • C. show high resistance with negative on anode and positive on cathode, and low resistance when reversed
  • D. show low resistance in both directions
  • Correct Answer: Option A