MCQOPTIONS
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MCQOPTIONS
This section includes 15 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. |
In the ___________ type of mounting the SCR is pressed between two heat sinks |
| A. | bolt-down mounting |
| B. | stud-mounting |
| C. | press-pak mounting |
| D. | cross-fit mounting |
| Answer» D. cross-fit mounting | |
| 2. |
For low power SCRs (about 1 Ampere current) _____________ type of mounting is used |
| A. | lead |
| B. | stud |
| C. | bolt-down |
| D. | press-fit |
| Answer» B. stud | |
| 3. |
Heat dissipation from heat sink mainly takes place by |
| A. | radiation |
| B. | convection |
| C. | absorption |
| D. | none of the mentioned |
| Answer» C. absorption | |
| 4. |
The sink to ambient thermal resistance of SCR θsA |
| A. | depends on the flatness of the device |
| B. | depends on the length of the device |
| C. | depends on the current carrying capabilities |
| D. | is independent on thyristor configuration |
| Answer» E. | |
| 5. |
The total thermal resistance between junction and ambient θjA is 10°C/W. θjc is 2°C/W. θcs is 4°C/W. θsA = ? |
| A. | 4°C/W |
| B. | 2°C/W |
| C. | 10°C/W |
| D. | 16°C/W |
| Answer» B. 2°C/W | |
| 6. |
IN_THE_____________TYPE_OF_MOUNTING_THE_SCR_IS_PRESSED_BETWEEN_TWO_HEAT_SINKS?$ |
| A. | bolt-down mounting |
| B. | stud-mounting |
| C. | press-pak mounting |
| D. | cross-fit mounting |
| Answer» D. cross-fit mounting | |
| 7. |
For low power SCRs (about 1 Ampere current) _____________ type of mounting is use? |
| A. | lead |
| B. | stud |
| C. | bolt-down |
| D. | press-fit |
| Answer» B. stud | |
| 8. |
Heat dissipation from heat sink mainly takes place b? |
| A. | radiation |
| B. | convection |
| C. | absorption |
| D. | none of the mentioned |
| Answer» C. absorption | |
| 9. |
Pav x (θjc + θcs + θsA) =$ |
| A. | Maximum specified temperature |
| B. | Energy lost |
| C. | Difference in temperature between junction & ambient |
| D. | Sum of junction & ambient temperature |
| Answer» D. Sum of junction & ambient temperature | |
| 10. |
The sink to ambient thermal resistance of SCR θsA$ |
| A. | depends on the flatness of the device |
| B. | depends on the length of the device |
| C. | depends on the current carrying capabilities |
| D. | is independent on thyristor configuration |
| Answer» E. | |
| 11. |
Which of the following thermal resistance parameters depends on the size of the device and the clamping pressure? |
| A. | θ<sub>sA</sub> |
| B. | θ<sub>cs</sub> |
| C. | θ<sub>jc</sub> |
| D. | None |
| Answer» C. ‚âà√≠‚Äö√†√®<sub>jc</sub> | |
| 12. |
The total thermal resistance between junction and ambient θjA is 10°C/W. θjc is 2°C/W. θcs is 4°C/W. θsA = ?$ |
| A. | 4°C/W |
| B. | 2°C/W |
| C. | 10°C/W |
| D. | 16°C/W |
| Answer» B. 2¬¨¬®‚Äö√†√ªC/W | |
| 13. |
The dv/dt rating of SCR can be improved by using |
| A. | cathode-short structure |
| B. | anode-short structure |
| C. | gate-short structure |
| D. | centre gate thyristor |
| Answer» B. anode-short structure | |
| 14. |
Inter-digitating of gate-cathode regions in SCR devices improves the |
| A. | I<sup>2</sup>t rating |
| B. | di/dt rating |
| C. | dv/dt rating |
| D. | thermal resistance |
| Answer» C. dv/dt rating | |
| 15. |
The usual way to accomplish higher gate current for improved di/dt rating is by using |
| A. | varistors |
| B. | pilot thyristors |
| C. | twisted cables |
| D. | op-amps |
| Answer» C. twisted cables | |