# Electronics and Communication Engineering - Power Electronics

Exercise : Power Electronics - Section 2
11.
The average load current supplied by a thyristor depends on
firing angle
firing frequency
magnitude of gate current
all of the above
Explanation:

The firing angle controls the period of conduction and hence average load current.

12.
A dc chopper is feeding an RLE load. The maximum steady state ripple is
Explanation:

(Imax - Imin)max = .

13.
In a 3 phase full wave regulator feeding a star connected resistance load the input voltage is 400 V line to line. The firing angle is 160°. The line to line output voltage would be
400 V
zero
Explanation:

In a three-phase full wave regulator, output voltage is zero if a ≥ 150°.

14.
A thyristor is reverse biased. A positive gate pulse is applied. The thyristor
will be turned on
may or may not turn on
will not turn on
will turn on after sometime
Explanation:

Thyristor can turn on only when it is forward biased.

15.
A single phase series converter is used for
high voltage output
high current output
high voltage and high current output
improving the circuit efficiency