Thermal voltage VT can be given by____________?

Related Mcqs:

1. 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

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

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

3. The average value of the output voltage in a step – down dc chopper is given by__________?

   A. V 0 = V s
   B. V 0 = D V s
   C. V 0 = V s / D
   D. V 0 = V s / ( 1 – D )

4. The effects of EMI can be reduced by____________?

   A. Suppressing emissions
   B. Reducing the efficiency of the coupling path
   C. Reducing the susceptibility of the receptor
   D. All of these

5. The power demand can be estimated approximately by____________?

   A. Load survey method
   B. Mathematical method
   C. Statistical method
   D. Economic parameters

6. 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

7. In current commutated DC-DC choppers, the voltage spike appears across the load when_____________?

   A. Voltage across the commutating inductances collapses
   B. The capacitance voltage adds to the supply voltage
   C. Both A. and B.
   D. None of these

8. 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

9. The ac voltage controller can be used for ___________?

   A. Lighting and heating control
   B. On – line transformer tap changing
   C. Soft starting
   D. All of these

10. The ac output voltage waveform of VSI and AC output current waveform of CSI respectively is composed of___________?

    A. High dv / dt, low di / dt
    B. Low dv / dt, low di / dt
    C. Low dv / dt, high di / dt
    D. High dv / dt, high di / dt