Example of a voltage clamping device______________?

Related Mcqs:

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

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

2. Under normal operating condition voltage clamping device offers impedance of_________?

   A. high value.
   B. low value.
   C. zero value.
   D. moderate value.

3. 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

4. A single phase one pulse controlled circuit has a resistance R and counter emf E load 400 sin(314 t) as the source voltage. For a load counter emf of 200 V, the range of firing angle control is _____?

   A. 30° to 150°.
   B. 30° to 180°.
   C. 60° to 120°.
   D. 60° to 180°.

5. 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

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. 4 thyristors rated 200 V in series. The operating voltage of the string is 600 V. Derating factor of the string is_____________________?

   A. 0.75
   B. 0.7
   C. 0.2
   D. 0.25

8. Voltage commutation circuit can be converted into a current commutation by interchanging the positions of____________?

   A. Diode and capacitor
   B. Capacitor and SCR
   C. Inductor and capacitor
   D. Capacitor and load

9. The on – state voltage drop of IGBT consists of__________?

   A. Drop across the collector junction
   B. Drop across the drift region
   C. Drop across MOSFET portion
   D. All of these

10. In a full bridge VSI, in order to avoid the short circuit across the DC bus and the undefined AC output voltage condition, the modulating technique should ensure that___________?

    A. Top switch of each leg is on at any instant
    B. Bottom switch of each leg is on at any instant
    C. Either A. or B.
    D. None of these