ELECTRICIAN 2nd YEAR MODULE – Electronic Practice ONLINE TEST

Question 1 of 69

1. Which biasing is required for an NPN transistor to function as an amplifier?

Base positive, emitter negative and collector positive

Base ground, emitter and collector positive

Base positive, emitter negative and collector negative

Base negative, emitter positive and collector negative

Question 1 of 69

Question 2 of 69

2. How many characters are in hexadecimal number system?

12

6

16

8

Question 2 of 69

Question 3 of 69

3. Which logic gate's operation is represented by this truth table?

NOT gate

NOR gate

OR gate

AND gate

Question 3 of 69

Question 4 of 69

4. What is the characteristic property of base material in a transistor?

Heavily doped and very larger

Lightly doped and very thin

Lightly doped and very larger

Heavily doped and very thin

Question 4 of 69

Question 5 of 69

5. What is the output DC voltage in half wave rectifier, if the input AC voltage is 24 volt?

9.6 Volt

10.8 Volt

24 Volt

12 Volt

Question 5 of 69

Question 6 of 69

6. What is the minimum and maximum value of a resistor with color bands: red, violet, orange, and gold?

24700Ω - 27300Ω

22400Ω - 33600Ω

25650Ω - 28350Ω

23750Ω - 26250Ω

Question 6 of 69

Question 7 of 69

7. What is the type of amplifier?

Push Pull Amplifier

Common Emitter Amplifier

Common Base Amplifier

Emitter Follower Amplifier

Question 7 of 69

Question 8 of 69

8. How is the gate terminal of N-channel JFET biased?

Gates are forward biased

Gates are reverse biased with source

Gates are reverse biased

Gates are forward biased with drain

Question 8 of 69

Question 9 of 69

9. What is the function of R1 variable resistor in a TRIAC circuit?

Protects the RFI filter from overloading

Controls the pulse rate for triggering the TRIAC

Protects from overload to TRIAC

Controls the current in R2

Question 9 of 69

Question 10 of 69

10. What is the reason for higher barrier voltage in silicon material?

Resistance is very low

Lower atomic number

Valence electrons are two only

Doping percentage is more

Question 10 of 69

Question 11 of 69

11. Which is the advanced version of power electronic component used in the output stage in drives?

IGBT

UJT

SCR

FET

Question 11 of 69

Question 12 of 69

12. How does the depletion region behave?

As conductor

As semiconductor

As resistor

As insulator

Question 12 of 69

Question 13 of 69

13. What is the purpose of DIAC in power control circuits?

For amplification

For triggering

As rectifier

As an oscillator

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Question 14 of 69

14. Why is a feedback network used in the oscillator?

To cancel second harmonic distortion

To cancel noise distortion

To phase shift the signal by 180°

To phase shift the signal by 60°

Question 14 of 69

Question 15 of 69

15. What is the type of amplifier circuit?

Common emitter amplifier

Common collector amplifier

Common base amplifier

Class B push pull amplifier

Question 15 of 69

Question 16 of 69

16. What is the name of this amplifier?

Class AB push pull amplifier

Common emitter amplifier

Common collector amplifier

Class B push pull amplifier

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Question 17 of 69

17. What is the peak voltage of 220V RMS AC voltage?

312.25 V

311.17 V

310.02 V

315.20 V

Question 17 of 69

Question 18 of 69

18. What is the output voltage if the center tap of transformer is open circuited in a full wave rectifier circuit?

Half of the rated output

One fourth of rated output

Zero voltage

Full rated output

Question 18 of 69

Question 19 of 69

19. Which logic gate's operation is represented by this truth table?

NAND

NOR

AND

NOT

Question 19 of 69

Question 20 of 69

20. What is the main application of uni junction transistor?

Triggering circuits

Regulator circuits

Amplification

Rectification

Question 20 of 69

Question 21 of 69

21. What is the function of a transistor if emitter to base and collector to base are forward biased?

Acts as an amplifier

Acts as an open circuit

Acts as a closed switch

Acts as an oscillator

Question 21 of 69

Question 22 of 69

22. What is the input ripple frequency (F_in) of full wave rectifier?

F_in = √2 F

F_in = 2Fin

F_in = ½ F

F_in = F

Question 22 of 69

Question 23 of 69

23. Which filter circuit is capable of removing voltage spikes in the rectifier circuit?

LC filter

RC filter

Capacitor input filter

Series inductor filter

Question 23 of 69

Question 24 of 69

24. Which device has very high input impedance, low noise output, good linearity and low inter-electrode capacity?

PNP transistor

Uni junction transistor

NPN transistor

Field effect transistor

Question 24 of 69

Question 25 of 69

25. Which is a passive component?

Diac

Diode

Capacitor

Transistor

Question 25 of 69

Question 26 of 69

26. Why are most semiconductor devices made from silicon compared to germanium?

High barrier voltage

High resistance range

High current carrying capacity

High thermal conductivity

Question 26 of 69

Question 27 of 69

27. What defect will occur in the radio if the pulsations are not removed from the input of the rectifier?

Improper tuning

No response

Works with low volume

Humming sound

Question 27 of 69

Question 28 of 69

28. Which circuit is essential to maintain oscillations in an oscillator circuit?

Rectifier with filter

Voltage multiplier

Negative feedback

Positive feedback

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Question 29 of 69

29. What is the name of this logic gate symbol? [Two input logic gate]

Two input NAND gate

Two input NOR gate

Two input OR gate

Two input AND gate

Question 29 of 69

Question 30 of 69

30. What is the effect if SCR is latched into conduction and gate current is removed in DC?

Output voltage will be reduced

SCR gets cut off

Current through SCR OFF

Gate loses control over conduction

Question 30 of 69

Question 31 of 69

31. What is the total turn-on time (t_ton) while transistor makes a transition from V₂ to V₁?

(t_ton)= t_r - t_s

(t_ton)= t_r+ t_d+ t_s

(t_ton)=  t_r -  t_d

(t_ton)= t_d + t_r

Question 31 of 69

Question 32 of 69

32. Which oscillator provides highly accurate stable frequency?

Hartley oscillator

Quartz crystal oscillator

R.C phase shift oscillator

Colpitts oscillator

Question 32 of 69

Question 33 of 69

33. What is the name of this three-terminal electronic device symbol?

IGBT

TRIAC

DIAC

SCR

Question 33 of 69

Question 34 of 69

34. What is the minimum voltage required in the base-emitter junction to conduct a silicon transistor?

0.8 V - 0.9 V

0.2 V - 0.3 V

0.4 V - 0.5 V

0.6 V - 0.7 V

Question 34 of 69

Question 35 of 69

35. Which device is made up of using the methods of point contact, grown, diffusion and alloy junctions?

Capacitor

Transistor

Resistor

Inductor

Question 35 of 69

Question 36 of 69

36. What is the purpose of using Binary Coded Decimal (BCD) system in digital circuits?

Storing the data inputs

Control the binary system

Segregating the input parameters

Interface to binary system

Question 36 of 69

Question 37 of 69

37. Which resistor determines the voltage gain in a common emitter amplifier?

R1

RL

Re

R2

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Question 38 of 69

38. What is the output voltage in the full wave rectifier circuit?

Double the rated output

Half the rated output

No output

Rated output

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Question 39 of 69

39. Which electronic circuit produces signal waves or pulses without an input?

Oscillator

Amplifier

Detector

Modulator

Question 39 of 69

Question 40 of 69

40. Which letter indicates the compound material cadmium sulphide?

'R'

'B'

'C'

'A'

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Question 41 of 69

41. Which doping material is used to make P-type semiconductor?

Antimony

Arsenic

Phosphorous

Boron

Question 41 of 69

Question 42 of 69

42. How can the input impedance of CRO be increased?

By increasing volts/cm attenuator switch position

By adding resistance to CRO probe

By increasing time/base attenuator switch position

By adding resistance to trigger level circuit

Question 42 of 69

Question 43 of 69

43. Which resistor is used to measure light intensity?

PTC

VDR

LDR

NTC

Question 43 of 69

Question 44 of 69

44. Which code indicates silicon semiconductor diode?

BY 126

IN 4007

2N 3055

OA 79

Question 44 of 69

Question 45 of 69

45. What is the reason for widened barrier in a reverse biased diode?

Electrons and holes are attracted towards supply terminals

Minority carriers in two materials are neutralized

Holes in P material attracted to negative terminal

Electron in N material is drifted to positive terminal

Question 45 of 69

Question 46 of 69

46. What is the main application of SCR (Silicon Controlled Rectifier)?

Oscillators

Amplifier

Speed control of motors

Multi vibrators

Question 46 of 69

Question 47 of 69

47. What is the difference in current control of MOSFET compared to JFETs?

Using P material instead of N material

Using N material gate instead of P material

Insulating layer instead of junction

Using N material instead of P material

Question 47 of 69

Question 48 of 69

48. What is the primary function of this transistor circuit?

Amplification

Switching

Oscillation

Modulation

Question 48 of 69

Question 49 of 69

49. What is the formula to calculate the resonance frequency in an oscillator circuit?

f_r = 1/2π√LC

f_in = 1/2π√LC

f_in = 1/√2πL/C

f_in =1/(LC)√2π

Question 49 of 69

Question 50 of 69

50. What is the main advantage of a class A amplifier?

Maximum voltage gain

Minimum distortion

Minimum signal to noise ratio losses

Maximum current gain

Question 50 of 69

Question 51 of 69

51. Which is an active component?

Inductor

Capacitor

Transistor

Resistor

Question 51 of 69

Question 52 of 69

52. Which multivibrator produces a repetitive pulse wave form output?

Monostable multivibrator

Bistable multivibrator

One shot multivibrator

Astable multivibrator

Question 52 of 69

Question 53 of 69

53. What is the main function of Uni Junction Transistor (UJT)?

Microphone input device

Relaxation oscillator

Loud speaker amplifier

Broadcast transmitter

Question 53 of 69

Question 54 of 69

54. What is the frequency of the displayed signal on CRO screen covered by 5 divisions with a time base setting of 0.2 microseconds?

10.0 KHz

1.0 KHz

100.0 KHz

1000.0 KHz

Question 54 of 69

Question 55 of 69

55. Which quadrant operation of SCR delivers heavy current in reverse biasing?

First quadrant

Second quadrant

Third quadrant

Fourth quadrant

Question 55 of 69

Question 56 of 69

56. What determines whether a material is a conductor, semiconductor or insulator?

Atomic number of the atom of the material

Atomic bonding structure of atom

Atomic weight of the atom of the material

Existence of valence electrons in atom

Question 56 of 69

Question 57 of 69

57. What is the effect of pinch-off voltage in JFET?

Width of channel has maximum value

Drain current becomes zero

No depletion region exists

Reverse bias voltage becomes zero

Question 57 of 69

Question 58 of 69

58. What is the purpose of connecting L1 through C1 to the transistor base?

Provides transistor biasing voltage

Provides positive feedback

Provides negative feedback

Provides DC supply

Question 58 of 69

Question 59 of 69

59. Which instrument provides a visual representation of measured quantities?

Cathode ray oscilloscope

Function generator

Voltage stabilizer

Radio frequency generator

Question 59 of 69

Question 60 of 69

60. What is the main application of a Field Effect Transistor (FET)?

Low input impedance device

Current control device

Positive feedback device

Voltage control device

Question 60 of 69

Question 61 of 69

61. Which type of control device is used in electronic fan regulator control circuits?

FET

UJT

DIAC

TRIAC

Question 61 of 69

Question 62 of 69

62. Why is the collector region physically made larger than emitter region in a transistor?

Output taken from collector terminal

It has to dissipate more heat

Collector region always operate with high voltage

Base collector region is reverse biased

Question 62 of 69

Question 63 of 69

63. Which quantity can be measured by CRO (Cathode Ray Oscilloscope)?

Power factor

Resistance

Frequency

Inductance

Question 63 of 69

Question 64 of 69

64. What is the use of time-base control switch or knob in the CRO?

Select intensity of the beam

Select sweep speed

Select input signal voltage

Select input voltage range

Question 64 of 69

Question 65 of 69

65. What is the power gain of CE amplifier with a voltage gain of 66 and β (Beta) of the transistor is 100?

0.66

1.5

166

6600

Question 65 of 69

Question 66 of 69

66. How can a decimal number be converted into binary number?

Multiplying decimal by 2

Multiplying decimal by 4

Divide decimal by 4

Dividing decimal by 2

Question 66 of 69

Question 67 of 69

67. Why is a snubber circuit used in the TRIAC motor control circuit?

To avoid false triggering

To maintain the motor speed constant

To increase the life of TRIAC

To increase the motor torque

Question 67 of 69

Question 68 of 69

68. Which electronic circuit generates AC signal without input?

Amplifier circuit

Filter circuit

Oscillator circuit

Rectifier circuit

Question 68 of 69

Question 69 of 69

69. Why is negative feedback required in amplifier circuits?

To reduce the distortion

To increase the output current gain

To increase the amplification factor

To increase the output voltage gain

Question 69 of 69