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. |
A single-phase half-wave thyristor circuit with R load is triggered at an angle of α = 0°. As such, the maximum value of the average output voltage would be given byConsider Vs = Vm sinωt. |
| A. | Vm |
| B. | 2Vm/π |
| C. | Vm/π |
| D. | Vm/α |
| Answer» D. Vm/α | |
| 2. |
For the below given circuit with firing angle α & angular frequency of ω, the circuit turn-off time in secs can be given by |
| A. | α/π |
| B. | π/α |
| C. | ω/π |
| D. | π/ω |
| Answer» E. | |
| 3. |
For a single phase thyristor circuit with R load & firing angle α, the conduction angle can be given by |
| A. | π+α |
| B. | 2π+α |
| C. | π-α |
| D. | α |
| Answer» D. α | |
| 4. |
Below shown ideal circuit is triggered at a firing angle of α. From ωt = π to 2π+α |
| A. | SCR voltage is zero |
| B. | Load voltage is maximum |
| C. | SCR voltage is –Vmsinα |
| D. | SCR acts like a short circuit |
| Answer» D. SCR acts like a short circuit | |
| 5. |
Below shown ideal circuit is triggered at a firing angle of α. The voltage across the SCR is zero from ωt = |
| A. | 0 to α |
| B. | 0 to π |
| C. | α to 2π |
| D. | α to π |
| Answer» E. | |
| 6. |
In a single phase half-wave thyristor circuit with R load & Vs=Vm sinωt, the maximum value of the load current can be given by |
| A. | 2Vm/R |
| B. | Vs/R |
| C. | Vm/2 |
| D. | Vs/2 |
| Answer» D. Vs/2 | |
| 7. |
In the method of phase control, the phase relationship between ___ & ___ is controlled by varying the firing angle |
| A. | supply current, supply voltage |
| B. | end of the load current, end of the load voltage |
| C. | start of the load current, start of the load voltage |
| D. | load current, load voltage |
| Answer» D. load current, load voltage | |
| 8. |
In the below given circuit, the SCR is triggered at a certain firing angle α.The load current falls to zero at ωt = |
| A. | α |
| B. | α/2 |
| C. | π |
| D. | π/2 |
| Answer» D. π/2 | |
| 9. |
The average output voltage is maximum when SCR is triggered at ωt = |
| A. | π |
| B. | 0 |
| C. | π/2 |
| D. | π/4 |
| Answer» C. π/2 | |
| 10. |
A voltage source Vs = Vm sinωt is connected in series with a resistance R and an SCR. At some firing angle delay of α a positive gate pulse is applied to the SCR which turns on the SCR. Considering ideal conditions, at the instant α the voltage at the resistor terminals Vo |
| A. | falls to zero |
| B. | falls to –Vm sin α |
| C. | rises to Vm sin α |
| D. | rises to Vm sin ωt |
| Answer» D. rises to Vm sin ωt | |