An SCR is made up of silicon because?

Related Mcqs:

1. The turn-on time of an SCR with inductive load is 20 µs. The puls train frequency is 2.5 KHz with a mark/space ratio of 1/10, then SCR will___________?

   A. Turn on
   B. Not turn on
   C. Turn on if inductance is removed
   D. Turn on if pulse frequency us increased to two times

2. A silicon controlled racitifier (SCR) is a ____________?

   A. Unijunction device
   B. Device with three junction
   C. Device with four junction
   D. None of the above

3. An SCR is made up of silicon because_____________?

   A. silicon has large leakage current than germanium
   B. silicon has small leakage current than germanium
   C. silicon has small leakage voltage than germanium
   D. silicon has large leakage voltage than germanium

4. The typical value of SCR for modern alternator is____________?

   A. 1.5.
   B. 0.5.
   C. 1.0.
   D. 1.2.

5. An SCR is considered to be a semi controlled device because_______?

   A. it can be turned OFF but not ON with a gate pulse.
   B. it conducts only during one half cycle of an alternating current wave.
   C. it can be turned ON but not OFF with a gate pulse.
   D. it can be turned ON only during one half cycle of an AC.

6. SCR will be turned off when anode current is_______________?

   A. < latching current but greater than holding current and gate signal is 0.
   B. less than holding current.
   C. < latching current but greater than holding current and gate signal is present.
   D. both (A) and (B).

7. 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

8. Which of the following is used in SCR to protect from high dV / dt__________________?

   A. Snubber circuit
   B. Fuse
   C. Equalizing circuit
   D. Circuit breaker

9. A string of n parallel SCRs is operated at 72 KA, the rating of each SCR is 1 KA. If derating factor of the string is 0.1. value of n will be___________?

   A. 60
   B. 70
   C. 80
   D. 90

10. Number of PN junction in an SCR is____________?

    A. Two
    B. Three
    C. Four
    D. Five