Exercise :: Power Electronics - Section 1
| 36. | A single phase half wave controlled rectifier circuit has a free wheeling diode. The load is a combination of R and L. The firing angle is a. The period of conduction of SCR and free wheeling diode respectively are |
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Answer: Option A Explanation: SCR conducts from a to p and free wheeling diode from p to (2p + a). |
| 37. | 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. |
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Answer: Option C Explanation: Transistors are used but not very widely. |
| 38. | In a thyristor the gate current is increased, then |
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Answer: Option C Explanation: Gate current does not affect the magnitude of anode current. |
| 39. | Thyristors are not suitable for logic circuits. |
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Answer: Option B Explanation: Thyristors can be used for logic circuits. |
| 40. | A single phase half wave rectifier is feeding a resistive load. Input voltage v = Vm sin ωt. The output dc voltage is Vdc and output rms voltage is Vrms . If firing angle is 180°, Vdc and Vrms respectively are |
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Answer: Option A Explanation: Put a = 180° in Eqs Otherwise also a = 180° means no conduction. Hence zero output voltage. |
