MCQOPTIONS
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MCQOPTIONS
This section includes 10 Mcqs, each offering curated multiple-choice questions to sharpen your Power Electronics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
___________ commutation technique is commonly employed in series inverters. |
| A. | line |
| B. | load |
| C. | forced |
| D. | external-pulse |
| Answer» C. forced | |
| 2. |
The natural reversal of ac supply voltage commutates the SCR in case of |
| A. | forced commutation |
| B. | only line commutation |
| C. | only natural commutation |
| D. | both line & natural commutation |
| Answer» E. | |
| 3. |
The type of commutation in which the pulse to turn off the SCR is obtained by separate voltage source is |
| A. | class B commutation |
| B. | class C commutation |
| C. | class D commutation |
| D. | class E commutation |
| Answer» E. | |
| 4. |
The type of commutation when the load is commutated by transferring its load current to another incoming thyristor is |
| A. | class A or load commutation |
| B. | class B or resonant commutation |
| C. | class C or complementary commutation |
| D. | class D or impulse commutation |
| Answer» D. class D or impulse commutation | |
| 5. |
An SCR is connected in series with L = 5 mH and C = 20 μF. Find the resonant frequency of the circuit. |
| A. | 2569 rad/s |
| B. | 3162 rad/s |
| C. | 2400 rad/s |
| D. | 7889 rad/s |
| Answer» C. 2400 rad/s | |
| 6. |
In case of class B commutation or resonant-pulse commutation with L = 5 μH and C = 20 μC with the initial voltage across the capacitor (Vs) = 230 V. Find the conduction time for auxiliary thyristor. |
| A. | 0.23 μs |
| B. | 6.57 μ |
| C. | 31.41 μs |
| D. | 56 μs |
| Answer» D. 56 μs | |
| 7. |
In case of class B commutation or resonant-pulse commutation with L = 5 μH and C = 20 μC with initial voltage across the capacitor (Vs) = 230 V. Find the peak value of resonant current. |
| A. | 560 A |
| B. | 460 A |
| C. | 360 A |
| D. | 260 A |
| Answer» C. 360 A | |
| 8. |
The class A commutation or load commutation is possible in case of |
| A. | dc circuits only |
| B. | ac circuits only |
| C. | both DC and AC circuits |
| D. | none of the above mentioned |
| Answer» B. ac circuits only | |
| 9. |
In case of class A type commutation or load commutation with low value of R load the |
| A. | L is connected across R |
| B. | L-C is connected across R |
| C. | L is connected in series with R |
| D. | L-C is connected in series with R |
| Answer» E. | |
| 10. |
The thyristor turn-off requires that the anode current |
| A. | falls below the holding current |
| B. | falls below the latching current |
| C. | rises above the holding current |
| D. | rises above the latching current |
| Answer» B. falls below the latching current | |