semiconductor diode Mcqs
1. The reverse current in a diode is of the order of _____________?
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A. mA

B. ?A

C. A

D. kA

2. The doping level in a zener diode is______________ that of a crystal diode?
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A. more than

B. the same as

C. less than

D. none of the above

3. A zener diode has ______________ breakdown voltage?
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A. zero

B. none of the above

C. sharp

D. undefined

4. If the PIV rating of a diode is exceeded,_______________?
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A. the diode is destroyed

B. the diode behaves like a zener diode

C. none of the above

D. the diode conducts poorly

5. A crystal diode has______________?
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A. two pn junctions

B. none of the above

C. three pn junctions

D. one pn junction
6. If the doping level of a crystal diode is increased, the breakdown voltage__________________?
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A. remains the same

B. none of the above

C. is decreased

D. is increased

7. Mains a.c. power is converrted into d.c. power for_________________?
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A. using in electronic equipment

B. lighting purposes

C. heaters

D. none of the above

8. A zener diode is destroyed if it______________?
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A. carrier more than rated current

B. is forward biased

C. is reverse biased

D. none of the above

9. A crystal diode has forward resistance of the order of ________________?
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A. ?

B. none of the above

C. k?

D. M?

10. The ripple factor of a half-wave rectifier is_________________?
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A. 2.5

B. 2

C. 0.48

D. 1.21

11. A crystal diode is used as______________?
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A. a voltage regulator

B. an oscillator

C. a rectifier

D. an amplifier

12. If the temperature of a crystal diode increases, then leakage current ______________?
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A. becomes zero

B. increases

C. decreases

D. remains the same

13. A half-wave rectifier has an input voltage of 240 V r.m.s. If the step-down transformer has a turns ratio of 8:1, what is the peak load voltage? Ignore diode drop?
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A. 42.5 V

B. 30 V

C. 86.5 V

D. 27.5 V

14. The most widely used rectifier is ________________?
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A. bridge full-wave rectifier

B. none of the above

C. centre-tap full-wave rectifier

D. half-wave rectifier

15. When a crystal diode is used as a rectifier, the most important consideration is ____________?
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A. reverse characteristic

B. PIC rating

C. doping level

D. forward characteristic

16. The leakage current in a crystal diode is due to _________________?
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A. minority carriers

B. none of the above

C. junction capacitance

D. majority carriers

17. A zener diode utilizes ______________ characteristics for its operation?
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A. forward

B. reverse

C. both forward and reverse

D. none of the above

18. The PIV rating of each diode in a bridge rectifier is ___________that of the equivalent center-tap rectifier?
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A. twice

B. the same as

C. one-half

D. four times

19. For the same secondary voltage, the output voltage from a centre-tap rectifier is___________ than that of bridge rectifier?
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A. four time

B. twice

C. thrice

D. one-half
20. In the breakdown region, a zener didoe behaves like a _______________source?
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A. none of the above

B. constant current

C. constant voltage

D. constant resistance

21. A crystal diode is a ________________device?
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A. none of the above

B. non-linear

C. bilateral

D. linear

22. The knee voltage of a crystal diode is approximately equal to ________________?
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A. breakdown voltage

B. barrier potential

C. applied voltage

D. forward voltage

23. If the arrow of crystal diode symbol is positive w.r.t. bar, then diode is _____________biased?
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A. none of the above

B. reverse

C. forward

D. either forward or reverse

24. A crystal diode utilises .. characteristic for rectification
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A. reverse

B. forward or reverse

C. none of the above

D. forward
25. A zener diode is used as ______________?
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A. a rectifier

B. a multivibrator

C. a voltage regulator

D. an amplifier

26. A series resistance is connected in the zener circuit to_______________?
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A. none of the above

B. protect the zener

C. properly reverse bias the zener

D. properly forward bias the zener

27. A 10 V power supply would use ____________ as filter capacitor?
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A. air capacitor

B. electrolytic capacitor

C. paper capacitor

D. mica capacitor

28. A zener diode has ________________?
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A. three pn junctions

B. two pn junctions

C. one pn junction

D. none of the above

29. If the a.c. input to a half-wave rectifier is an r.m.s value of 400/?2 volts, then diode PIV rating is__________________?
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A. 400 x ?2 V

B. 400/?2 V

C. 400 V

D. none of the above

30. When the crystal current diode current is large, the bias is ______________?
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A. forward

B. reverse

C. inverse

D. poor

31. ____________ rectifier has the lowest forward resistance?
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A. vacuum tube

B. none of the above

C. solid state

D. gas tube

32. If the doping level in a crystal diode is increased, the width of depletion layer_____________?
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A. in increased

B. is decreased

C. none of the above

D. remains the same

33. When the graph between current through and voltage across a device is a straight line, the device is referred to as _______________?
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A. passive

B. nonlinear

C. active

D. linear
34. The maximum efficiency of a half-wave rectifier is _____________?
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A. 81.20%

B. 50%

C. 40.6 %

D. 25%

35. The d.c. resistance of a crystal diode is ______________ its a.c. resistance?
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A. none of the above

B. the same as

C. more than

D. less than
36. The ratio of reverse resistance and forward resistance of a germanium crystal diode is about ______________?
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A. 1000:01:00

B. 40,000 : 1

C. 1:01

D. 100:01:00

37. A zener diode is always_______________ connected?
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A. reverse

B. none of the above

C. forward

D. either reverse or forward

38. _____________ filter circuit results in the best voltage regulation?
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A. none of the above

B. resistance input

C. capacitor input

D. choke input
39. A zener diode is________________ device?
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A. a linear

B. none of the above

C. an amplifying

D. a non-linear
40. The forward voltage drop across a silicon diode is about _______________?
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A. 0.7 V

B. 3 V

C. 10 V

D. 2.5 V

41. There is a need of transformer for__________________?
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A. centre-tap full-wave rectifier

B. none of the above

C. half-wave rectifier

D. bridge full-wave rectifier

42. A 1,000 V power supply would use_____________ as a filter capacitor?
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A. air capacitor

B. paper capacitor

C. electrolytic capacitor

D. mica capacitor

43. The disadvantage of a half-wave rectifier is that the__________________?
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A. components are expensive

B. none of the above

C. output is difficult to filter

D. diodes must have a higher power rating

44. The PIV rating of a crystal diode is _______________ that of equivalent vacuum diode
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A. none of the above

B. more than

C. lower than

D. the same as