With increase in firing angle,

Related Mcqs:

1. 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°.

2. The maximum firing angle in the half wave controlled regulator is_____________?

   A. 180 degree
   B. 190 degree
   C. 200 degree
   D. 210 degree

3. In a 3 phase half wave rectifier, when firing angle is less than 90 degree, then the average dc output voltage becomes__________________?

   A. Positive
   B. Negative
   C. Zero
   D. None of these

4. If the firing angle becomes negative, then the rectifier begins to work as_______________?

   A. A rectifier
   B. An inverter
   C. A chopper
   D. A regulator

5. The phase angle of gate signal in TRIAC can be shifted by using_____________?

   A. A capacitor
   B. A variable resistor
   C. An inductor
   D. Only (a) and (b)

6. The maximum di/dt in a SCR is____________?

   A. Directly proportional to supply voltage
   B. Directly proportional to inductance in the circuit
   C. Inversely proportional to supply voltage
   D. Both A and B

7. Thermal voltage VT can be given by____________?

   A. Kq/T
   B. KT/q
   C. qT/K
   D. (K2/q)(T + 1/T – 1)

8. For series connected SCR’s dynamic equalising circuit consists of___________?

   A. R and C in series but with diode across C
   B. R and C in series but with diode across R
   C. Series R and diode with C across R
   D. Series R and diode with C across R

9. In a 3 phase bridge rectifier the ripple frequency is _____________?

   A. Equal to the input frequency
   B. Twice the input frequency
   C. Three times the input frequency
   D. Six times the input frequency

10. Very large values of modulation index (greater than 3.24) lead to___________?

    A. Square AC output voltage
    B. Sine AC output voltage
    C. Triangular AC output voltage
    D. Trapezoidal AC output voltage