Q. Current derating may be necessary when thyristors are operating in

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Q. If duty cycle is a and the load is α resistance R, the rms value of output voltage is

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Q. For a BJT, α = 0.98, then β =

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Q. Assertion (A): Power transistor has lower switching time than SCR

Reason (R): Power transistor has greater switching time than SCR

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Q. A 3 kV circuit uses SCR of 800 V rating. If derating is 25%, the number of SCRs in series is

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Q. The number of doped regions in a SCR is

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Q. All inverters use forced commutation.

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Q. In 180° mode of operation of a 3 phase bridge inverter, two thyristors conduct at one time.

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Q. In a single phase full wave ac regulator the rms value of load current is 20 A load is purely resistive. Then

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Q. A reactor is used in a dual converter operating in non-circulating current mode.

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Q. In a 3 phase full wave regulator feeding resistance load connected in star, the possible range of firing angle α is

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Q. Assertion (A): A dual converter may be circulating current type or non circulating current type.

Reason (R): In circulating current dual converter only one converter can be operated at one time.

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Q. Current chopping leads to

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Q. A 3 phase bridge inverter is fed by 400 V battery. The load is star connected and has a resistance of 10 Ω per phase. The peak value of load current is

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Q. In an SCR, the anode current is controlled by

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Q. The rated current of a thyristor is 40 A. The holding current will be about :

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Q. A cycloconverter is

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Q. The number of leads in a power semiconductor diode are

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Q. If ton and toff are the turn on and turn off times of a thyristor, then

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Q. Assertion (A): The gate current of an SCR is always in the form of pulses.

Reason (R): The gate losses, in pulse triggering, are low.

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