Power Electronics - Study Mode

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[#86] It is required to deliver an output DC power of 500 W to a resistive load. The transformer rating required in case of half-wave, conventional full-wave and bridge rectifiers, respectively, is

(A) 1.7 kW, 616 W, 871 W

(B) 1.7 kW, 871 W, 616 W

(C) 616 kW, 1.7 W, 871 W

(D) 871 kW, 616 W, 1.7 W

Correct Answer

(B) 1.7 kW, 871 W, 616 W

[#87] A single phase full wave mid-point thyristor uses a 220/200 V transformer with central tap on the secondary side. The PIV per thyristor will be:

(A) 282.84 V

(B) 333.98 V

(C) 789.87 V

(D) 556. 34 V

Correct Answer

(A) 282.84 V

[#88] In dc chopper if T on is the on-time and f is the chopping frequency, then output voltage in terms on input voltage, V s is given by

(A) V s * T on /f

(B) V s * f/T on

(C) V s /f * T on

(D) V s * f * T on

Correct Answer

(D) V s * f * T on

[#89] Which semiconductor device acts like a diode and two resistors?

(A) SCR

(B) Triac

(C) Diac

(D) UJT

Correct Answer

(D) UJT

[#90] A triac is a . . . . . . . . switch

(A) Bidirectional

(B) Unidirectional

(C) Mechanical

(D) None of the above

Correct Answer

(A) Bidirectional