MCQOPTIONS
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MCQOPTIONS
This section includes 35 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which of these is the best description for a Zener diode ? |
| A. | It is a diode |
| B. | It is a constant current device |
| C. | It is a constant-voltage device |
| D. | It works in the forward region |
| Answer» D. It works in the forward region | |
| 2. |
Zener diode are generally made of _____________? |
| A. | Germanium |
| B. | Silicon |
| C. | Carbon |
| D. | None of the above |
| Answer» C. Carbon | |
| 3. |
Zener diode can be used as__________________? |
| A. | ac. voltage regulator only |
| B. | dc. voltage regulator only |
| C. | both D.C and A.C voltage regulator |
| D. | none of the above |
| Answer» D. none of the above | |
| 4. |
When load current is zero, the Zener current will be_____________? |
| A. | Zero |
| B. | Minimum |
| C. | Maximum |
| D. | None of the above |
| Answer» D. None of the above | |
| 5. |
What is true about the breakdown voltage in a Zener diode ? |
| A. | It decreases when load current increases |
| B. | It destroys the diode |
| C. | It equals current times the resistance |
| D. | It is approximately constant |
| Answer» E. | |
| 6. |
Two similar 15 V Zeners are connected in series. What is the regulated output voltage ? |
| A. | 15 V |
| B. | 5 V |
| C. | 30 V |
| D. | 45 V |
| Answer» D. 45 V | |
| 7. |
The Zener current will be minimum when_____________? |
| A. | Load current is maximum |
| B. | Load current is minimum |
| C. | Load current is zero |
| D. | None of the above |
| Answer» B. Load current is minimum | |
| 8. |
The rupture of co-valent bonds will occur when the electric field is__________________? |
| A. | 100 V/cm |
| B. | 6 V/cm |
| C. | 1000 V/cm |
| D. | More than 105 V/cm |
| Answer» E. | |
| 9. |
The load voltage is approximately constant when a Zener diode is ________________? |
| A. | Forward biased |
| B. | Unbiased |
| C. | Reverse biased |
| D. | Operating in the breakdown region |
| Answer» E. | |
| 10. |
The current in a Zener diode is limited by _______________? |
| A. | External resistance |
| B. | Power dissipation |
| C. | Both (A) and (B) |
| D. | None of the above |
| Answer» D. None of the above | |
| 11. |
In an unregulated power supply, if load current increases, the output voltage _____________? |
| A. | Remains the same |
| B. | Decreases |
| C. | Increases |
| D. | None of the above |
| Answer» C. Increases | |
| 12. |
In an unregulated power supply, if input a.c. voltage increases, the output voltage _______________? |
| A. | Increases |
| B. | Decreases |
| C. | Remains the same |
| D. | None of the above |
| Answer» B. Decreases | |
| 13. |
In a Zener voltage regulator, the changes in load current produce changes in _________________? |
| A. | Zener current |
| B. | Zener voltage |
| C. | Zener voltage as well as Zener current |
| D. | None of the above |
| Answer» B. Zener voltage | |
| 14. |
In a regulated power supply, two similar 15 V zeners are connected in series. The input voltage is 45 V d.c. If each Zener has a maximum current rating of 300 mA, what should be the value of the series resistance ? |
| A. | 10 O |
| B. | 50 O |
| C. | 25 O |
| D. | 40 O |
| Answer» C. 25 O | |
| 15. |
In a loaded Zener regulator, which is the largest Zener current ? |
| A. | Series current |
| B. | Zener current |
| C. | Load current |
| D. | None of the above |
| Answer» B. Zener current | |
| 16. |
In a 15 V Zener diode , the breakdown mechanism will occur by ______________? |
| A. | Avalanche mechanism |
| B. | Zener mechanism |
| C. | Both Zener and avalanche mechanism |
| D. | None of the above |
| Answer» B. Zener mechanism | |
| 17. |
If the load resistance decreases in a Zener regulator, then Zener current ______________? |
| A. | Decreases |
| B. | Stays the same |
| C. | Increases |
| D. | None of the above |
| Answer» B. Stays the same | |
| 18. |
If the load current drawn by unregulated power supply increases, the d.c. output voltage______________? |
| A. | Increases |
| B. | Decreases |
| C. | Stays the same |
| D. | None of the above |
| Answer» C. Stays the same | |
| 19. |
If the load current drawn by unregulated power supply increases, the d.c. output voltage _____________? |
| A. | Increases |
| B. | Decreases |
| C. | Stays the same |
| D. | None of the above |
| Answer» C. Stays the same | |
| 20. |
If the doping level is increased, the breakdown voltage of the Zener_______________? |
| A. | Remains the same |
| B. | Is increased |
| C. | Is decreased |
| D. | None of the above |
| Answer» D. None of the above | |
| 21. |
For increasing the voltage rating, zeners are connected in_____________? |
| A. | Parallel |
| B. | Series-parallel |
| C. | Series |
| D. | None of the above |
| Answer» D. None of the above | |
| 22. |
Commercial power supplies have voltage regulation ______________? |
| A. | of 10% |
| B. | of 15% |
| C. | of 25% |
| D. | within 1% |
| Answer» E. | |
| 23. |
As the junction temperature increases, the voltage breakdown point for Zener mechanism _______________? |
| A. | Is increased |
| B. | Is decreased |
| C. | Remains the same |
| D. | None of the above |
| Answer» C. Remains the same | |
| 24. |
As the junction temperature increases, the voltage breakdown point for avalanche mechanism______________? |
| A. | Remains the same |
| B. | Decrease |
| C. | Increases |
| D. | None of the above |
| Answer» D. None of the above | |
| 25. |
Another name for Zener diode is ______________diode? |
| A. | Breakdown |
| B. | Voltage |
| C. | Power |
| D. | Current |
| Answer» B. Voltage | |
| 26. |
An ideal regulated power supply is one which has voltage regulation of________________? |
| A. | 0% |
| B. | 5% |
| C. | 10% |
| D. | 1% |
| Answer» B. 5% | |
| 27. |
A Zener voltage regulator will cease to act as a voltage regulator if Zener current becomes______________? |
| A. | Less than load current |
| B. | Zero |
| C. | More than load current |
| D. | None of the above |
| Answer» C. More than load current | |
| 28. |
A Zener voltage regulator is used for ____________ load currents? |
| A. | High |
| B. | Very high |
| C. | Moderate |
| D. | Small |
| Answer» E. | |
| 29. |
A Zener regulator _____________ in the power supply? |
| A. | Increases the ripple |
| B. | Decreases the ripple |
| C. | Neither increases nor decreases the ripple |
| D. | Data insufficient |
| Answer» C. Neither increases nor decreases the ripple | |
| 30. |
A Zener diode______________? |
| A. | Is a battery |
| B. | Acts like a battery in the breakdown region |
| C. | Has a barrier potential of 1 V |
| D. | Is forward biased |
| Answer» C. Has a barrier potential of 1 V | |
| 31. |
A Zener diode utilises_____________characteristic for voltage regulation? |
| A. | Forward |
| B. | Reverse |
| C. | Both forward and reverse |
| D. | None of the above |
| Answer» C. Both forward and reverse | |
| 32. |
A Zener diode that has very narrow depletion layer will breakdown by____________ mechanism? |
| A. | Avalanche |
| B. | Zener |
| C. | Both avalanche and Zener |
| D. | None of the above |
| Answer» C. Both avalanche and Zener | |
| 33. |
A Zener diode is used as a _____________voltage regulating device? |
| A. | Shunt |
| B. | Series |
| C. | Series-shunt |
| D. | None of the above |
| Answer» B. Series | |
| 34. |
A power supply which has voltage regulation of ____________ is unregulated power supply? |
| A. | 0 % |
| B. | 5 % |
| C. | 10 % |
| D. | 8% |
| Answer» D. 8% | |
| 35. |
A power supply has a voltage regulation of 1%. If the no-load voltage is 20 V, what is the full-load voltage ? |
| A. | 8 V |
| B. | 7 V |
| C. | 6 V |
| D. | 2 V |
| Answer» B. 7 V | |