gate electronics & instrumentation full prep. test questions)

GATE Electronics & Instrumentation Full Prep. Test 1(Questions)

Duration- 3 Hours. Total Marks= 100. 2/3 will be deducted for each wrong answer

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18. Voltage regulators normally use

a. Negative feedbackb. Positive feedbackc. No feedbackd. Phase limiting

19. During regulation, the power dissipation of the pass transistor equals the collector-emitter voltage times the

a. Base currentb. Load currentc. Zener currentd. Foldback current

20. Without current limiting, a shorted load will probably

a. Produce zero load currentb. Destroy diodes and transistorsc. Have a load voltage equal to the zener voltaged. Have too little load current

21. A current-sensing resistor is usually

a. Zerob. Smallc. Larged. Open22. Simple current limiting produces too much heat in the

a. Zener diodeb. Load resistorc. Pass transistord. Ambient air

23. With foldback current limiting, the load voltage approaches zero, and the load current approaches



a. A small valueb. Infinityc. The zener currentd. A destructive level

24. A capacitor may be needed in a discrete voltage regulator to preventa. Negative feedbackb. Excessive load currentc. Oscillationsd. Current sensing

25. If the output of a voltage regulator varies from 15 to 14.7 V between the minimum and maximum load current, theload regulation is

a. 0b. 1%c. 2%d. 5%

26. If the output of a voltage regulator varies from 20 to 19.8 V when the line voltage varies over its specified range, thesource regulation is The output impedance of a voltage regulator is

a. Very smallb. Very largec. Equal to the load voltage divided by the load currentd. Equal to the input voltage divided by the output current

27. Compared to the ripple into a voltage regulator, the ripple out of a voltage regulator isa. Equal in valueb. Much largerc. Much smallerd. Impossible to determine

28. A voltage regulator has a ripple rejection of -60 dB. If the input ripple is 1 V, the output ripple isa. -60 mVb. 1 mVc. 10 mVd. 1000 V

29. Thermal shutdown occurs in an IC regulator ifa. Power dissipation is too highb. Internal temperature is too highc. Current through the device is too highd. All the above occur

30. If a linear three-terminal IC regulator is more than a few inches from the filter capacitor, you may get oscillationsinside the IC unless you use

a. Current limitingb. A bypass capacitor on the input pinc. A coupling capacitor on the output pind. A regulated input voltage



31. The 78XX series of voltage regulators produces an output voltage that isa. Positiveb. Negativec. Either positive or negatived. Unregulated

32. The 78XX-12 produces a regulated output voltage ofa. 3 Vb. 4 Vc. 12 Vd. 40 V

33. A current booster is a transistor ina. Series with the IC regulatorb. Parallel with the IC regulatorc. Either series or paralleld. Shunt with the load

34. To turn on a current booster, we can drive its base-emitter terminals with the voltage acrossa. A load resistorb. A zener impedancec. Another transistord. A current-sensing resistor

35. A phase splitter produces two output voltages that area. Equal in phaseb. Unequal in amplitudec. Opposite in phased. Very small

36. A series regulator is an example of aa. Linear regulatorb. Switching regulatorc. Shunt regulatord. Dc-to-dc converter

37. The emitter is at ac ground in a

a. CB stageb. CC stagec. CE staged. None of these

38. The output voltage of a CE stage is usually

a. Constantb. Dependent on re'c. Smalld. Less the one

39. The voltage gain equals the output voltage divided by the



a. Input voltageb. AC emitter resistancec. AC collector resistanced. Generator voltage

40. The input impedance of the base increases when

a. Beta increasesb. Supply voltage increasesc. Beta decreasesd. AC collector resistance increases

41. Voltage gain is directly proportional to

a. Betab. Ac emitter resistancec. DC collector voltaged. AC collector resistance

42. Compared to the ac resistance of the emitter diode, the feedback resistance of a swamped amplifier should be

a. Smallb. Equalc. Larged. Zero

43. Compared to a CE stage, a swamped amplifier has an input impedance that is

a. Smallerb. Equalc. Largerd. Zero

44. To reduce the distortion of an amplified signal, you can increase the

a. Collector resistanceb. Emitter feedback resistancec. Generator resistanced. Load resistance

45. The emitter of a swamped amplifier

a. Is groundedb. Has no de voltagec. Has an ac voltaged. Has no ac voltage

46. A swamped amplifier uses

a. Base bias



b. Positive feedbackc. Negative feedbackd. A grounded emitter

47. In a swamped amplifier, the effects of the emitter diode become

a. Important to voltage gainb. Critical to input impedancec. Significant to the analysisd. Unimportant

48. The feedback resistor

a. Increases voltage gainb. Reduces distortionc. Decreases collector resistanced. Decreases input impedance

49. The feedback resistor

a. Stabilizes voltage gainb. Increases distortionc. Increases collector resistanced. Decreases input impedance

50. An oscillator always needs an amplifier with

a. Positive feedbackb. Negative feedbackc. Both types of feedbackd. An LC tank circuit

51. The voltage that starts an oscillator is caused by

a. Ripple from the power supplyb. Noise voltage in resistorsc. The input signal from a generatord. Positive feedback

52. The Wien-bridge oscillator is usefula. At low frequenciesb. At high frequenciesc. With LC tank circuitsd. At small input signals

53. A lag circuit has a phase angle that isa. Between 0 and +90 degreesb. Greater than 90 degreesc. Between 0 and -90 degreesd. The same as the input voltage



54. A coupling circuit is aa. Lag circuitb. Lead circuitc. Lead-lag circuitd. Resonant circuit

55. A lead circuit has a phase angle that isa. Between 0 and +90 degreesb. Greater than 90 degreesc. Between 0 and -90 degreesd. The same as the input voltage

56. A Wien-bridge oscillator usesa. Positive feedbackb. Negative feedbackc. Both types of feedbackd. An LC tank circuit

57. Initially, the loop gain of a Wien-bridge oscillator isa. 0b. 1c. Lowd. High

58. A Wien bridge is sometimes called a

a. Notch filterb. Twin-T oscillatorc. Phase shifterd. Wheatstone bridge

59. To vary the frequency of a Wien bridge, you can vary

a. One resistorb. Two resistorsc. Three resistorsd. One capacitor

60. The phase-shift oscillator usually has

a. Two lead or lag circuitsb. Three lead or fag circuitsc. A lead-lag circuitd. A twin-T filter

gate electronics & instrumentation full prep. test questions)

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