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WorksheetsU21EE502 PED - UNIT 1
Total questions: 10
Worksheet time: 5mins
1. How do you categories the converter and inverter grade SCR?
a. Based on Turn On time
b. Based on Turn off time
c. Based on Commutation methods
d. Power rating
2.Which Power Semiconductor Device out of the following, is not a current controlled device?
a. SCR
b. TRIAC
c. GTO
d. MOSFET
3.The minimum duration of the pulse in a pulse triggering system for thyristors should be at -----------
a.10 μs 3 sec
b. 20 ms
c. 10 ms
d. 3 sec
4.Which one of the following statement is true?
A.MOSFET has a positive temperature coefficient whereas BJT has a negative temperature coefficient
B.Both MOSFET and BJT have positive temperature coefficient
C. Both MOSFET and BJT have negative temperature coefficient
D.MOSFET has negative temperature coefficient whereas BJT has positive temperature coefficient
5.The conduction losses in IGBT is
A. More than that of MOSFET
B. Lower than that of MOSFET
C. Equal to that of MOSFET
D. Equal to that of BJT
6. In Class A and Class B commutation, the resonating circuit has to be
A.Over Damped
B. Critically Damped
C. Under Damped
D. Nagatively Damped
7. For triggering of SCR used UJT, has the waveform
A. Sine Wave
B. Square Wave
C. Sawtooth Wave
D. Trapezoidal Wave
8. 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.
9. A freewheeling diode is connected across an inductive load is
A.To restore conduction angle on phase
B. To avoid negative reversal voltage drop
C. To reduce the PRV
D. All of the above
10. When a line commutated converter operates in the inverter mode
A. It draws both real and reactive power from the AC supply
B. It delivers both real and reactive power to the AC supply
C. It delivers real power to the AC supply
D. It draws reactive power from the AC supply
