Q. Assertion (A): The circuit of figure thyristor will conduct for 180° during positive half cycle if it is continuously fired.

Reason (R): A thyristor can conduct only when it is forward biased.

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Q. In the below figure, the load is highly inductive. The firing angle is a for each of the thyristors. The periods of conduction of Th1 and Th2 respectively are

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Q. The condition for underdamped oscillations in a series RLC circuit is

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Q. A single phase fully controlled bridge converter is fed by a voltage Vm sin ωt. The average and rms values of output voltage are

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Q. Which of the following is correct for a BJT?

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Q. A fully controlled bridge converter is feeding an RLE load. The load current is I₀. The input voltage is Vm sin ωt. The KVL equation to find firing angle α is

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Q. The duty cycle of a step down chopper is

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Q. A rectifier is fed by a transformer. The rms voltage and current at secondary of transformer are Vs and Is. Output dc power is Vdc Idc and output ac power is (Vrms ) (Irms), Transformer utilisation factor TUF is

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Q. If Ar and Ac are the amplitudes of reference and control signals, the modulation index M is

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Q. For a single phase half wave converter feeding a resistive load, the firing angle a. The waveshape in below figure is for

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Q. A single phase fully controlled bridge converter is feeding an RLE load. Input voltage is Vm sin ωt and firing angle is α. If average current is I₀, then

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Q. Which of the following is not between F2 layer and D layer?

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Q. A cycloconverter can be

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Q. In a 3 phase fully controlled converter the firing frequency is

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Q. Two thyristor of same rating and same specifications

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Q. The amount of dielectric heating is inversely proportional to frequency.

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Q. A semiconverter feeding an RLE load operates in

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Q. The phenomenon of overlap in converter operation due to

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Q. A thyristor has a maximum allowable junction temperature of 120°C and the ambient temperature is 40°C. If thermal resistance is 1.6° C/W, the maximum allowable internal power dissipation is

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Q. For a 12 pulse operation, the two 6 pulse units are fed by

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