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_____?

Related Mcqs:

1. The curve between V and I of SCR when anode is positive w.r.t cathode and when anode is negative w.r.t cathode are known as_____________________?

   A. both as forward characteristics
   B. both as reverse characteristics
   C. former as forward characteristics and later as reverse characteristics
   D. former as reverse characteristics and later as forward characteristics

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. In EMC signal, the source delivers maximum power to the input of transmission line when the transmission line input impedance

   A. Is equal to the source resistance
   B. Greater than the source resistance
   C. Smaller than the source resistance
   D. None of these

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

   A. anode current decreases
   B. anode current does not decrease at all
   C. anode current increases
   D. cathode current increases

5. 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

6. 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

7. A modern power semiconductor device that combines the characteristic of BJT and MOSFET is_____________?

   A. IGBT
   B. FCT
   C. MCT
   D. GTO

8. An SCR has half cycle surge current rating of 3000 A for 50 Hz supply. One cycle surge current will be_____?

   A. 1500 A.
   B. 6000 A.
   C. 2121.32 A.
   D. 4242.64 A.

9. 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

10. 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