Saturday, May 28, 2011

Basic Questions in Power Electronics


1.      In load commutation the load circuit is  ___________
a)      Damped
b)      Oscillatory
c)      Resistive
d)      Over damped

2.      Auxillary or voltage commutation uses a
a)      L,C & auxillary thyristor
b)      R,L,&diac
c)      R,L,C,& thyristor
d)      None of above

3.      Class F commutation is known as
a)      External Pulse commutation
b)      Forced commutation
c)      Natural commutation
d)      Self commutation

4.      Applications of  forced commutation is
a)      Choppers
b)      Cycloconverters
c)      Controlled rectifiers
d)      None of the above

5.      Thyristors have high di/dt ratings and can withstand surges also-TRUE/FALSE

6.      Gate of a SCR is also called as
a)      DRIVE terminal
b)      Gate-cathode
c)      Anode gate
d)      Nne of the above

7.      The leakage current through the reverse biased p-n junction(J2) doubles for every ____ rise in temperature
a)      7 deg/c
b)      12 deg/c
c)      10 deg/c
d)      8 deg/c

8.      Snubber circuit used for protecting the SCR against large
a)      large surges
b)      large dv/dt
c)      large di/dt
d)      large dT/dt ( where T=temperature)

9.      Class  D commutation uses
a)      Diode,thyristor and RLC
b)      Triac,transistor and RLC
c)      UJT,diode
d)      Two Thyristors

10.  Class E is a
a)      Forced commutation
b)      Natural commutation
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