Multiple Choice Questions and Answers on Semiconductor Diode

Multiple Choice Questions and Answers on Semiconductor Diode

Q1. A crystal diode has ………

  1. one pn junction
  2. two pn junctions
  3. three pn junctions
  4. none of the above

Answer : 1

Q2. A crystal diode has forward resistance of the order of ……………

  1. Ω
  2. none of the above

Answer : 2

Q3. If the arrow of crystal diode symbol is positive w.r.t. bar, then diode is ………….. biased.

  1. forward
  2. reverse
  3. either forward or reverse
  4. none of the above

Answer : 1

Q4. The reverse current in a diode is of the order of ……………….

  1. kA
  2. mA
  3. μA
  4. A

Answer : 3

Q5. The forward voltage drop across a silicon diode is about …………………

  1. 2.5 V
  2. 3 V
  3. 10 V
  4. 0.7 V

Answer : 4

Q6. A crystal diode is used as ……………

  1. an amplifier
  2. a rectifier
  3. an oscillator
  4. a voltage regulator

Answer : 2

Q7. The d.c. resistance of a crystal diode is ………….. its a.c. resistance

  1. the same as
  2. more than
  3. less than
  4. none of the above

Answer : 3

Q8. An ideal crystal diode is one which behaves as a perfect ……….. when forward biased.

  1. conductor
  2. insulator
  3. resistance material
  4. none of the above

Answer : 1

Q9. The ratio of reverse resistance and forward resistance of a germanium crystal diode is about ………….

  1. 1 : 1
  2. 100 : 1
  3. 1000 : 1
  4. 40,000 : 1

Answer : 4

Q 10. The leakage current in a crystal diode is due to …………….

  1. minority carriers
  2. majority carriers
  3. junction capacitance
  4. none of the above

Answer :1

Q11. If the temperature of a crystal diode increases, then leakage current ………..

  1. remains the same
  2. decreases
  3. increases
  4. becomes zero

Answer :3

Q12. The PIV rating of a crystal diode is ………….. that of equivalent vacuum diode

  1. the same as
  2. lower than
  3. more than
  4. none of the above

Answer :2

Q13. If the doping level of a crystal diode is increased, the breakdown voltage………….

  1. remains the same
  2. is increased
  3. is decreased
  4. none of the above

Answer :3

Q14. The knee voltage of a crystal diode is approximately equal to ………….

  1. applied voltage
  2. breakdown voltage
  3. forward voltage
  4. barrier potential

Answer :4

Q15. When the graph between current through and voltage across a device is a straight line, the device is referred to as ……………….

  1. linear
  2. active
  3. nonlinear
  4. passive

Answer :1

Q16. When the crystal current diode current is large, the bias is …………

  1. forward
  2. inverse
  3. poor
  4. reverse

Answer :1

Q17. A crystal diode is a …………… device

  1. non-linear
  2. bilateral
  3. linear
  4. none of the above

Answer :1

Q18. A crystal diode utilises …………….. characteristic for rectification

  1. reverse
  2. forward
  3. forward or reverse
  4. none of the above

Answer :2

Q19. When a crystal diode is used as a rectifier, the most important consideration is ………..

  1. forward characteristic
  2. doping level
  3. reverse characteristic
  4. PIC rating

Answer :4

Q20. If the doping level in a crystal diode is increased, the width of depletion layer………..

  1. remains the same
  2. is decreased
  3. in increased
  4. none of the above

Answer :3

Q21. A zener diode has ………..

  1. one pn junction
  2. two pn junctions
  3. three pn junctions
  4. none of the above

Answer :1

Q22. A zener diode is used as …………….

  1. an amplifier
  2. a voltage regulator
  3. a rectifier
  4. a multivibrator

Answer :2

Q23. The doping level in a zener diode is …………… that of a crystal diode

  1. the same as
  2. less than
  3. more than
  4. none of the above

Answer :3

Q24. A zener diode is always ………… connected.

  1. reverse
  2. forward
  3. either reverse or forward
  4. none of the above

Answer :1

Q25. A zener diode utilizes ……….. characteristics for its operation.

  1. forward
  2. reverse
  3. both forward and reverse
  4. none of the above

Answer :2

Q26. In the breakdown region, a zener didoe behaves like a …………… source.

  1. constant voltage
  2. constant current
  3. constant resistance
  4. none of the above

Answer :1

27. A zener diode is destroyed if it…………..

  1. is forward biased
  2. is reverse biased
  3. carrier more than rated current
  4. none of the above

Answer :3

Q28. A series resistance is connected in the zener circuit to………..

  1. properly reverse bias the zener
  2. protect the zener
  3. properly forward bias the zener
  4. none of the above

Answer :2

A29. A zener diode is …………………. device

  1. a non-linear
  2. a linear
  3. an amplifying
  4. none of the above

Answer :1

Q30. A zener diode has ………….. breakdown voltage

  1. undefined
  2. sharp
  3. zero
  4. none of the above

Answer :2

Q31. ……………. rectifier has the lowest forward resistance

  1. solid state
  2. vacuum tube
  3. gas tube
  4. none of the above

Answer :1

Q32. Mains a.c. power is converrted into d.c. power for ……………..

  1. lighting purposes
  2. heaters
  3. using in electronic equipment
  4. none of the above

Answer :3

Q33. The disadvantage of a half-wave rectifier is that the……………….

  1. components are expensive
  2. diodes must have a higher power rating
  3. output is difficult to filter
  4. none of the above

Answer :3

Q34. 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 ………………….

  1. 400/√2 V
  2. 400 V
  3. 400 x √2 V
  4. none of the above

Answer :2

Q35. The ripple factor of a half-wave rectifier is …………………

  1. 2
  2. 1.21
  3. 2.5
  4. 0.48

Answer :4

Q36. There is a need of transformer for ………………..

  1. half-wave rectifier
  2. centre-tap full-wave rectifier
  3. bridge full-wave rectifier
  4. none of the above

Answer :2

Q37. The PIV rating of each diode in a bridge rectifier is ……………… that of the equivalent centre-tap rectifier

  1. one-half
  2. the same as
  3. twice
  4. four times

Answer :1

Q38. For the same secondary voltage, the output voltage from a centre-tap rectifier is ………… than that of bridge rectifier

  1. twice
  2. thrice
  3. four time
  4. one-half

Answer :4

Q39. If the PIV rating of a diode is exceeded, ………………

  1. the diode conducts poorly
  2. the diode is destroyed
  3. the diode behaves like a zener diode
  4. none of the above

Answer :2

Q40. A 10 V power supply would use …………………. as filter capacitor.

  1. paper capacitor
  2. mica capacitor
  3. electrolytic capacitor
  4. air capacitor

Answer :3

Q41. A 1,000 V power supply would use ……….. as a filter capacitor

  1. paper capacitor
  2. air capacitor
  3. mica capacitor
  4. electrolytic capacitor

Answer :1

Q42. The ……………….. filter circuit results in the best voltage regulation

  1. choke input
  2. capacitor input
  3. resistance input
  4. none of the above

Answer :1

Q43. 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.

  1. 27.5 V
  2. 86.5 V
  3. 30 V
  4. 42.5 V

Answer :4

Q44. The maximum efficiency of a half-wave rectifier is ………………..

  1. 40.6 %
  2. 81.2 %
  3. 50 %
  4. 25 %

Answer :1

Q45. The most widely used rectifier is ……………….

  1. half-wave rectifier
  2. centre-tap full-wave rectifier
  3. bridge full-wave rectifier
  4. none of the above

Answer :3