Thyristor(SCR) Objective Type Questions with Answers

Power Electronics Objective Type Questions with Answers on SCR

1. An SCR is made of silicon and not germanium because silicon ....
(1) is inexpensive
(2) is mechanically strong
(3) has small leakage current
(4) is tetravalent

2. An SCR is a solid state equivalent of ...
(1) Triode
(2) Pentode
(3) Gas-filled triode
(4) Tetrode

3. An SCR behaves as a ............... switch
(1) Unidirectional
(2) Bidirectional
(3) Mechanical
(4) None of the above

4. An SCR has three terminals viz. ...
(1) cathode, anode, gate
(2) anode, cathode, grid
(3) anode, cathode, drain
(4) none of the above

5. An SCR is made of
(1) Germanium
(2) Silicon
(3) Carbon
(4) None of the above

(a) 1 only
(b) 2 only
(c) 1 & 2 only
(d) 1,2,3 only

6. An SCR is also known as
(1) Triac
(2) Diac
(3) Unijunction transistor
(4) Thyristor

7. In the normal operation of an SCR, anode is ........ with respect to cathode
(1) at zero potential
(2) negative
(3) positive
(4) none of the above

8. An SCR combines the features of ........
(1) a rectifier and resistance
(2) a rectifier and transistor
(3) a rectifier and capacitor
(4) none of the above

9. In normal operation of an SCR, gate is .......... with respect to cathode
(1) positive
(2) negative
(3) at zero potential
(4) none of the above

10. When SCR is OFF, the current in the circuit is .........
(1) exactly zero
(2) small leakage current
(3) large leakage current
(4) none of the above

11. The control element in an SCR is .......
(1) cathode
(2) anode
(3) anode supply
(4) gate

12. The normal way to turn on an SCR is by.......
(1) Breakover voltage
(2) Appropriate anode current
(3) Appropriate gate current
(4) None of the above

13. An SCR is turned off by ........
(1) Reducing anode voltage to zero
(2) Reducing gate voltage to zero
(3) Reverse biasing the gate
(4) None of the above