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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Q. In a single phase full wave converter (M - 2 connection) feeding a highly inductive load, the firing angle for each thyristor is a in the respective half cycle. The period of conduction of each thyristor is

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Q. If Vdc1 is the dc output voltage in half wave controlled rectifier circuit feeding resistive load and Vdc2 is the dc output voltage in full wave controlled rectifier circuit (M - 2 connection) feeding resistive load, then

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Q. A semi converter operates in two quadrants.

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Q. Assertion (A): An ideal rectifier should have unity harmonic factor

Reason (R): An ideal rectifier should have unity displacement factor.

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Q. A single phase half wave rectifier is feeding a resistive load. When α = 0, dc output voltage is 127 V. When α = 30°, the dc output voltage will be about

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Q. A two winding transformer is feeding a single phase half wave rectifier circuit. The load is purely resistive. The rms value of transformer secondary current is Is and rms value of load current in Irms. Then

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Q. The terminals of a power BJT are called

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Q. In single phase half wave regulator, the average current over one full cycle

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Q. The dynamic equalising circuit consists of a series combination of capacitor C and resistor RC across each thyristor. This resistance RC (along with parallel connected diode)

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Q. A single phase semiconverter is feeding a highly inductive load and has freewheeling diode across the load. The waveshapes of output voltage and output current

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Q. An SCR is triggered at 40° in the positive half cycle only. The average anode current is 50 A. If the firing angle is changed to 80°, the average anode current is likely to be

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Q. The characteristics of a non-linear resistance is i = kv⁴. If i becomes 100 times, v becomes

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Q. In a step down chopper using pulse width modulation, Ton = 3 x 10¯³ and Toff = 1 x 10¯³ s. The chopping frequency is

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Q. Thyristors are suitable for dc circuit breakers but not for ac circuit breakers.

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Q. Assertion (A): Inverters and choppers use fast switching thyristors

Reason (R): Fast switching SCR has low turn off time.

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