If the gate voltage of an SCR is removed, then the_______________?

Related Mcqs:

1. For an SCR gate – cathode characteristic is a straight line of 130. For triggered source volume of 15 V and allowable gate power dissipation of 0.5 W compute the gate source resistance_____?

   A. 111.9 Ω.
   B. 11.19 Ω.
   C. 108 Ω.
   D. 115 Ω

2. 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

3. With gate open, the maximum anode current at which SCR is turned off from ON condition is called____________?

   A. breakdown voltage
   B. peak reverse voltage
   C. holding current
   D. latching current

4. ON state voltage drop across SCR lie between the range_____________?

   A. 0 – 0.5 V.
   B. 0.5 – 1 V.
   C. 1 – 1.5 V.
   D. 1.5 – 2 V.

5. A thyristor string is made of a no. of SCR connected in series and parallel. The string have volume and current of 11 KV and 4 KA. The voltage and current rating of available SCRs are 1800 V and 1000 A. For a string efficiency of 90 % let the number of SCRs in series and parallel are a and b respectively. Then the value of a and b will be_____________?

   A. 5, 7
   B. 4, 6
   C. 7, 5
   D. 6, 4

6. Let of a thyristor Vc1, Vc2, Vc3 are forward break over voltage for gate current Ig1, Ig2, Ig3 respectively. Then________________?

   A. Vc1 > Vc2 > Vc3 when Ig1 > Ig2 > Ig3.
   B. Vc1 > Vc2 > Vc3 when Ig1 < Ig2 < Ig3.
   C. Vc1 = Vc2 = Vc3 any value of Ig.
   D. Vc1 > Vc2 > Vc3 when Ig1 ≥ Ig2 &Atil

7. A step up chopper has input voltage 110 V and output voltage 150 V. The value of duty cycle is_____?

   A. 0.32
   B. 0.67
   C. 0.45
   D. 0.27

8. Under over voltage condition impedance offered by the voltage clamping device is__________?

   A. low
   B. High
   C. moderate
   D. infinity

9. In the operation and control of both naturally commutated and forced commutated SCR base converter, commutation plays an important role. The converters is / are ___________?

   A. AC – DC
   B. DC – DC
   C. DC – AC
   D. All of these

10. An SCR can be used___________?

    A. as static conductor
    B. for power control
    C. for speed control of dc shunt motor
    D. All of these