In a single phase full wave regulator feeding R-L load, the minimum firing angle can be zero.
Answer: A
Range of control of a is 0 ≤ a ≤ p.
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Two thyristor of same rating and same specifications
Answer: C
Turn on and turn off times of similar SCRs may not be same.
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An SCR has a turn on time of 4 μs. The gate pulse should have a duration of about
Answer: B
Duration of gate pulse should be slightly more than turn time of SCR.
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A high frequency series inverter consists of
Answer: B
A high frequency series inverter has many series inverters in parallel. Only one inverter operates at one time and they operate in fixed sequence.
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Assertion (A): A transistor requires a continuous base signal for conduction but a thyristor requires a gate pulse.
Reason (R): Transistor find widespread application in power electronic circuits.
Answer: C
Transistors are used but not very widely.
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A semiconverter feeding an RLE load operates in
Answer: A
Semiconvertor operates only in first quadrant.
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A static induction thyristor
Answer: B
It can be turned on by positive gate pulse and turned off by negative gate pulse. It is minority carrier device. It can be manufactured in high current and high voltage ratings and its on state voltage drops is low.
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A cycloconverter cannot give a frequency higher than input frequency.
Answer: B
Step up cycloconverter can give a frequency higher than input frequency.
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In a 3 phase semiconverter, the firing frequency is
Answer: B
Since the circuit has 3 thyristors, firing frequency is three times the line frequency.
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A dc separately excited motor has a constant field current. The armature is fed from a single phase supply through a semi-converter. When a = 0, speed is 600 rpm. If a = 90°, the speed is likely to be
Answer: A
Average output voltage is reduced to 50% if a = 90°. Hence speed is also reduced to 50%.
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