Exercise :: Power Electronics - Section 1
| 11. | 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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Answer: Option C Explanation:
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.| 12. | The characteristics of a non-linear resistance is i = kv4. If i becomes 100 times, v becomes |
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Answer: Option C Explanation: v ∝ (i)1/4 ∝ (100)1/4 ≈ 3. |
| 13. | 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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Answer: Option B Explanation:
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.| 14. | Thyristors are suitable for dc circuit breakers but not for ac circuit breakers. |
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Answer: Option B Explanation: They are suitable for both dc and ac circuit breakers. |
| 15. | Assertion (A): Inverters and choppers use fast switching thyristors Reason (R): Fast switching SCR has low turn off time. |
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Answer: Option A Explanation: Low turn off time enables fast switching. |