Silicon Controlled Rectifier (SCR) MCQ

Silicon Controlled Rectifier (SCR) MCQ

Silicon Controlled Rectifier (SCR) MCQ, Multiple Choice Questions on Silicon Controlled Rectifier (SCR), SCR MCQ, Engineering MCQ, Electronics MCQ, Electronics Devices MCQ

Semiconductor Diode MCQ

Multiple Choice Questions

Q.1. An SCR has p-n junctions.

  • two
  • three
  • four
  • none of the above

Answer: three

Q.2. An SCR is a solid-state equivalent of ………

  • triode
  • pentode
  • gas-filled triode
  • tetrode

Answer: gas-filled triode

Q.3. An SCR has …… semiconductor layers.

  • two
  • three
  • four
  • none of the above

Answer: four

Q.4. An SCR has three terminals viz. ……….  

  • cathode, anode, gate
  • anode, cathode, grid
  • anode, cathode, drain
  • none of the above

Answer: cathode, anode, gate

Q.5. An SCR behaves as a …….. switch.

  • unidirectional
  • bidirectional
  • mechanical
  • none of the above

Answer: unidirectional

Q.6. An SCR is sometimes called ………

  • triac
  • diac
  • unijunction transistor
  • thyristor

Answer: thyristor

Q.7. An SCR is made of ………

  • germanium
  • silicon
  • carbon
  • none of the above

Answer: silicon

Q.8. In the normal operation of an SCR, the anode is ………..  w.r.t. cathode.

  • at zero potential
  • negative
  • positive
  • none of the above

Answer: positive

Q.9. In the normal operation of an SCR, the gate is ……… w.r.t. cathode.

  • positive
  • negative
  • at zero potential
  • none of the above

Answer: positive

Q.10. An SCR combines the features of ………

  • a rectifier and resistance
  • a rectifier and transistor
  • a rectifier and capacitor
  • none of the above

Answer: a rectifier and transistor

Q.11. The control element in an SCR is ……………

  • cathode
  • anode
  • anode supply
  • gate

Answer: gate

Q.12. The normal way to turn on an SCR is by ……

  • breakover voltage
  • appropriate anode current
  • appropriate gate current
  • none of the above

Answer: appropriate gate current

Q.13. An SCR is turned off by …………

  • reducing anode voltage to zero
  • reducing gate voltage to zero
  • reverse biasing the gate
  • none of the above

Answer: reducing anode voltage to zero

Q.14. An SCR is a ……. triggered device.

  • voltage
  • current
  • voltage as well as current
  • none of the above

Answer: current

Q.15. In an SCR circuit, the supply voltage is generally ………..  that of break-over voltage.

  • equal to
  • less than
  • greater than
  • none of the above

Answer: less than

Q.16. When an SCR is turned on, the voltage, across it is about ……….

  • zero
  • 10 V
  • 0.1 V
  • 1 V

Answer: 1 V

Q.17. An SCR is made of silicon and not germanium because of silicon …………..

  • is inexpensive
  • is mechanically strong
  • has small leakage current
  • is tetravalent

Answer: has small leakage current

Q.18. An SCR is turned off when …………..

  • anode current is reduced to zero
  • gate voltage is reduced to zero
  • gate is reverse biased
  • none of the above

Answer: anode current is reduced to zero

Q.19. In an SCR circuit, the angle of conduction can be changed by ………..

  • changing anode voltage
  • changing gate voltage
  • reverse biasing the gate
  • none of the above

Answer: changing gate voltage

Q.20. If the firing angle in an SCR circuit is increased, the output ……………

  • remains the same
  • is increased
  • is decreased
  • none of the above

Answer: is decreased

Q.21. If gate current is increased, then anode-cathode voltage at which SCR closes …….

  • is decreased
  • is increased
  • remains the same
  • none of the above

Answer: is decreased

Q.22. When SCR is OFF, the current in the circuit is……………

  • exactly zero
  • small leakage current
  • large leakage current
  • none of the above

Answer: small leakage current

Q.23. An SCR can exercise control over …………. of a.c. supply.

  • positive half-cycles only
  • negative half-cycles only
  • both positive and negative half-cycles
  • positive or negative half-cycles

Answer: positive or negative half-cycles

Q.24. We can control a.c. power in a load by connecting  

  • two SCRs in series
  • two SCRs in parallel
  • two SCRs in parallel opposition
  • none of the above

Answer: two SCRs in parallel opposition

Q.25. When SCR starts conducting, then …………… loses all control.

  • gate
  • cathode
  • anode
  • none of the above

Answer: gate

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