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Upwork Electronics

Semiconductor Electronics Test 2016

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1. An SCR is a solid state equivalent of a _____.

Answers:

  1. triode
  2. pentode
  3. thyratron
  4. diode

2. If the input to an integrating circuit is a square wave, the output will be _____.

Answers:

  1. triangular
  2. rectangular
  3. saw-tooth
  4. spiked

3. A P-type material is _____.

Answers:

  1. positively charged
  2. negatively charged
  3. electrically neutral
  4. none of the above

4. The stability factor of a biasing circuit is 10. What does it mean?

Answers:

  1. Ic changes 10 times as munch as any change in Ico(leakage current)
  2. Ib changes 10 times as much as any change in Ico
  3. Ie change 10 times as munch as any change in Ico

5. According to the Barkhausen criterion for oscillators_______.

A – open loop gain
ß – feed back factor

Answers:

  1. Aß < 1
  2. Aß > 1
  3. Aß = 1
  4. Aß = 1

6. If the reverse bias on the gate of an FET is increased , the width of the conducting channel will _____.

Answers:

  1. increase
  2. decrease
  3. remain constant

7. An FET has the following parameters IDSS = 32mA , VGS ( off ) = -8V , VGS = -4.5V. What will be the drain current?

Answers:

  1. 5.2 mA
  2. 6.12 mA
  3. 7.03 mA
  4. 7.45 mA

8. For good stabilization of the operating point in a voltage divider bias, the current I, flowing through potential dividers R1 and R2, should be equal to or greater than _____.
(IB-base current)

Answers:

  1. 2IB
  2. 10IB
  3. 4IB
  4. IB/2

9. If in a transistor IE = 10.5mA , IC = 10mA,the value of ß will be _____.

Answers:

  1. 0.2
  2. 200
  3. 100
  4. 20

10. The slope of the D.C load line of a transistor circuit having a collector load Rc is _____.

Answers:

  1. Rc
  2. 1/Rc
  3. -1/Rc
  4. 2Rc

11. Tuning is generally accomplished by varying _____.

Answers:

  1. L(inductor)
  2. C(capacitor)
  3. both L and C
  4. R(resistor)

12. A triac can pass a portion of _____.

Answers:

  1. positive half-cycle through the load
  2. negative half-cycle through the load
  3. both positive and negative half-cycles through the load
  4. None of the above

13. An A.C supply of 230v is applied to a half wave rectifier circuit through a transformer of turn ratio 10:1. Its D.C voltage output will be _____.

Answers:

  1. 5v
  2. 12v
  3. 10.36v
  4. 5.18v

14. A vacuum tube conducts current _____.

Answers:

  1. from the cathode to the anode
  2. from the anode to the cathode
  3. in both the above directions
  4. alternately in both directions

15. If a circuit of full-wave centre-tapped rectifier with capacitor filter employs a load RL = 100O, and C = 1050µF and the frequency is 50HZ , what would be the ripple factor?

Answers:

  1. 40%
  2. 30%
  3. 22%
  4. 27%

16. Two identical germanium diodes are connected in series opposition. A 10V battery is impressed upon this series arrangement. What will be the voltage across each diode room temperature if the Zener breakdown voltage of each diode is 9.8V?

Answers:

  1. VD1= 0.2V , VD2 = 9.8V
  2. VD1 = 10V , VD2 = 0V
  3. VD1 = 0V , VD2 = 10V
  4. VD1 = 9.8V , VD2 = 0.2V

17. A varactor diode can function as a variable capacitor with a________ forward bias.

Answers:

  1. very slight
  2. moderate
  3. heavy

18. Radio frequencies have their range above _____.

Answers:

  1. 20KHZ
  2. 50KHZ
  3. 100KHZ
  4. 200KHZ

19. Tuned amplifiers are generally operated as

Answers:

  1. class A amplifiers
  2. class B amplifiers
  3. class AB amplifiers
  4. class C amplifiesrs

20. In the collector feedback biasing, ß = 57 , RC = 1 kO , IB = 60µA and VCB = 4.5V. The value of the stability factor will be _____.

Answers:

  1. 30.4
  2. 32.9
  3. 57
  4. 4.5

21. In the enhancement mode (MOSFET) , conductivity increases _____.

Answers:

  1. with the decrease in positive gate voltage
  2. with the increase in positive gate voltage
  3. with the decrease in negative gate voltage
  4. with the increase in negative gate voltage

22. A three-stage amplifier has a first-stage voltage gain of 100, a second stage voltage gain of 200 and a third stage gain of 400. The total voltage gain in db will be _____.

Answers:

  1. 130 dB
  2. 140 dB
  3. 132 dB
  4. 138 dB

23. The output characteristics of an FET closely resemble the plate characteristics of a________ valve.

Answers:

  1. diode
  2. triode
  3. tetrode
  4. pentode

24. The Q-factor of a parallel tuned circuit is given by _____.

Answers:

  1. 1/RvC/L
  2. RvL/C
  3. 1/RvL/C
  4. RvC/L

25. At parallel resonance, a tuned circuit offers an impedance of _____.

Answers:

  1. C/LR
  2. R/LC
  3. L/CR
  4. 2L/CR

26. When a transistor has to act as a switch, it must operate in _____.

Answers:

  1. the active region
  2. the cut-off region
  3. the saturation region
  4. both the cut off and the saturation regions

27. The V-I characteristics of a triac in the first and third quadrants are essentially identical to those of _______ in the first quadrant

Answers:

  1. a transistor
  2. a UJT
  3. a zener diode
  4. an SCR

28. In the d.c. equivalent circuit of a transistor amplifier , the capacitors are regarded as _____.

Answers:

  1. Open
  2. Short
  3. Sometimes open and sometimes short
  4. Unchanged

29. The output frequency of a half-wave rectifier is _____.

Answers:

  1. double the input A.C frequency
  2. half the input A.C frequency
  3. equal to the input A.C frequency
  4. None of the above

30. The maximum efficiency of a full wave rectifier is _____.

Answers:

  1. 40%
  2. 81.2%
  3. 90%
  4. 99%

31. If the collector supply voltage is 10v, the collector cut off voltage under D.C conditions will be _____.

Answers:

  1. 5v
  2. 10v
  3. 20v
  4. 30v

32. The relationship among bandwidth, resonant frequency and Q of a tuned circuit is _____.

Answers:

  1. BW = Q/fr
  2. BW = Q fr
  3. BW = frvQ
  4. BW = fr/Q

33. Why is the control grid of a tube always held at negative potential W.R.T cathode.?

Answers:

  1. in order to avoid heating of the tube
  2. in order to obtain faithful amplification
  3. in order to set its operating point
  4. None of the above

34. If in a transistor , Ic = 9.5mA , Ie = 10mA , the value of a will be _____.

Answers:

  1. 0.95
  2. 10
  3. 9.5
  4. 0.095

35. In an R-C phase shift oscillator, an R-C network is designed to introduce a phase shift of _____ .

Answers:

  1. 300
  2. 600
  3. 900
  4. 1800

36. If the input to a differentiating circuit is a square wave, the output will be _____.

Answers:

  1. rectangular
  2. spiked
  3. triangular
  4. sinusoidal

37. For faithful amplification, VBE must not fall below _____.

Answers:

  1. 0.9v for si transistors
  2. 0.5v for si transistors
  3. 0.3v for si transistors
  4. 0.7v for si transistors

38. Tuned amplifiers are used for the amplification of _____.

Answers:

  1. audio frequencies
  2. RF
  3. very low frequencies
  4. very high frequencies

39. For an R-C phase shift oscillator , the frequency of oscillation will be given as _____.

Answers:

  1. fo = 1/2?vRC
  2. fo = 1/2?v6RC
  3. fo = 1/v2?RC
  4. fo = 2/v2?RC

40. A reversed biased P-N junction has a resistance of the order of _____.

Answers:

  1. O
  2. KO
  3. MO
  4. mO

41. The impedance of a parallel tuned circuit at resonance is _____.

Answers:

  1. 0
  2. low
  3. very high
  4. very low

42. A transistor amplifier has 4v,2mA as the operating point. For faithful amplification, the collector current due to signal alone should not exceed _____.

Answers:

  1. 2mA
  2. 1mA
  3. 4mA
  4. 8mA

43. A D.C milliammeter connected to a half-wave rectifier supplying a maximum current of 10mA will read _____.

Answers:

  1. 10 mA
  2. 20 mA
  3. 5 mA
  4. 3.18 mA

44. An SCR combines the features of_____.

Answers:

  1. a rectifier and an amplifier
  2. a rectifier and a transistor
  3. a rectifier and an oscillator
  4. a rectifier and an inverter

45. Hartley oscillator is _____.

Answers:

  1. an RC oscillator
  2. an LC oscillator
  3. a Crystal oscillator

46. If in a transistor VCB= 4V , VBE = 0.7V, the VCE will be equal to _____.

Answers:

  1. 4.7v
  2. 5.4v
  3. 3.3v
  4. 0.7v

47. Vacuum tubes are _____.

Answers:

  1. linear devices
  2. non-linear devices
  3. both linear and non-linear under different conditions

 

48. The input and output voltages of a CE transistor amplifier are _____.

Answers:

  1. in phase
  2. 90° out of phase
  3. 180° out of phase
  4. 120° out of phase

49. An FET has ________ temperature co-efficient of resistance.

Answers:

  1. 0
  2. positive
  3. negative

50. An :FET is a _____.

Answers:

  1. bipolar device
  2. tripolar device
  3. unipolar device

51. The complementary MOS(CMOS) uses _____.

Answers:

  1. only n-channel devices in the circuit
  2. only p- channel devices in the circuit
  3. both n and p channel devices in the circuit
  4. None of the above

52. When a transistor is driven to saturation, ideally, the Vce is _____.

Answers:

  1. VCC
  2. VCC/2
  3. 0
  4. 2VCC

53. A 3-ohm load is coupled to a transistor amplifier through a step-down transformer. If the D.C resistance of the primary winding is 300O and the output resistance of the amplifier is 3KO, what should be the turn ratio for the transfer of maximum power?

Answers:

  1. Np/Ns=40
  2. Np/Ns=20
  3. Np/Ns=30
  4. Np/Ns=10

54. The ideal value of the stability factor is _____.

Answers:

  1. 0
  2. 10
  3. 1
  4. 100

55. If the A.C input to a half-wave rectifier has an R.M.S valve of 400/v2 v, the peak inverse voltage will be _____.

Answers:

  1. 400 v
  2. 400v2 v
  3. 800v2 v
  4. 800/v2 v

1,039 total views, 3 views today

Upwork Electronics

Fiber Optics Test 2016

Published by:

1. For a step index fiber, relationship between numerical aperture (NA) and coupling efficiency (ηc) is ________.

Answers:

  1. a
  2. b
  3. c
  4. d

2. Mirrors are placed in LASER optical sources to maintain conditions for ________.

Answers:

  1. incoherence
  2. amplification
  3. modulation
  4. coherence

3. Optical bandwidth (OB) relates to electrical bandwidth (EB) when

Answers:

  1. OB<EB
  2. OB=EB
  3. OB>EB
  4. OB≥EB

4. What is the thermal noise current it in a resistor R expressed in its mean square value?

where, K is Boltzmann’s constant, T is absolute temperature and B is the bandwidth

Answers:

  1. a
  2. b
  3. c<>
  4. d

5. For a profile parameter (α)=1, the profile shape of refractive index for a graded index fiber will be _______.

Answers:

  1. triangular
  2. parabolic
  3. step
  4. circular

6. The rays which travel in a helical path through an optical fiber are called ______.

Answers:

  1. refracted rays
  2. reflected rays
  3. infra-red rays
  4. skew rays

7. Dark spot defects (DSD’s) occur in:

Answers:

  1. Non-semiconductor LASER
  2. Fiber LASER
  3. Glass fiber LASER
  4. Injection LASER

8. What happens when dispersion occurs?

Answers:

  1. Output transmitted pulse broadens
  2. Output transmitted pulse shortens
  3. Output transmitted pulse gets completely eliminated
  4. None of the above

9. Silicon reach through avalanche photodiodes has _______.

Answers:

  1. maximum absorption of photons
  2. maximum absorption of electrons
  3. maximum quantum efficiency
  4. minimum noise

10. The vapor-phase deposition technique is used to produce _______.

Answers:

  1. fiber-rich glasses
  2. silica-rich glasses
  3. oxide-rich glasses
  4. carbonate-rich glasses

11. Scattering losses happen due to:

Answers:

  1. a rise in temperature
  2. imperfections in glass manufacturing process
  3. humidity
  4. bending of fiber

12. Graded-index fibers have:

Answers:

  1. a constant refractive index in the core
  2. a variable refractive index in the cladding
  3. a variable refractive index in the core
  4. None of these

13. Dispersion in optical fibers causes distortion in _______.

Answers:

  1. analog signals only
  2. digital signals only
  3. both analog and digital signals
  4. infra-red signals only

14. The LASER is a/an

Answers:

  1. incoherent device
  2. switching device
  3. threshold device
  4. incandescent device

15. SONET is _________.

Answers:

  1. Scattered optical network
  2. Synchronous optical network
  3. Stable optical network
  4. Silicon optical network

16. In p-i-n photodiodes “i” stands for:

Answers:

  1. Internal
  2. Intrinsic
  3. Impurity
  4. None of the above

17. Dispersion is the lowest in a________.

Answers:

  1. Multimode step-index fiber
  2. Multimode graded-index fiber
  3. Single-mode step-index fiber
  4. Silicon fiber

18. Superluminescent LED’s are preferred because of _______.

Answers:

  1. large spectral linewidth
  2. a directional output beam
  3. low output power
  4. small size

19. Total internal reflection takes place at angles ________.

Answers:

  1. greater than the critical angle
  2. less than the critical angle
  3. equal to the critical angle
  4. None of the above

20. LED is more suitable for analog transmission because of its _______.

Answers:

  1. linearity
  2. bandwidth (spectrum)
  3. modulation property
  4. output power

21. When optical power is incident on the photo detector during the 0 bit period, then the system is said to exhibit _______.

Answers:

  1. a non-zero extinction ratio
  2. a zero extinction ratio
  3. an infinity extinction ratio
  4. an infinity absorption ratio

22. Which of the following is a fiber dispersion measurement method?

Answers:

  1. Time domain measurement
  2. Interferometric method
  3. Refracted near field method
  4. Reflected near field method

23. Germanium photodiodes are generally not preferred in the optical fiber system because of _________.

Answers:

  1. large current gain
  2. large voltage gain
  3. temperature dependence
  4. large dark current

24. Which one of the following is a type of non-linear scattering?

Answers:

  1. Stimulated Raman scattering (SRS)
  2. Rayleigh scattering
  3. Mie scattering
  4. Ultraviolet scattering

25. Refer to the figure above.

The critical angle at the core cladding interface is given by:

Answers:

  1. a
  2. b
  3. c
  4. d

26. Intersymbol interference (ISI) in optical fibers occurs due to ______.

Answers:

  1. refraction
  2. scattering
  3. bending
  4. dispersion

27. Near-field scanning method is used to measure:

Answers:

  1. Fiber attenuation
  2. Fiber dispersion
  3. Fiber numerical aperture
  4. Fiber refractive index profile

28. Which phenomenon does not let light rays escape an optical fiber?

Answers:

  1. Total internal reflection
  2. Total internal refraction
  3. Total internal diffraction
  4. Total internal attenuation

29. Quantum efficiency (η) is defined as

Answers:

  1. a
  2. b
  3. c
  4. d

30. Which of the following is an Optical System Design Software?

Answers:

  1. MATLAB
  2. COMSIM
  3. Photonic Transmission Design Suite (PTDS)
  4. ORCAD

31. COBRA (commutateur optique binaire rapide) is an ________.

Answers:

  1. optical fiber
  2. optical source
  3. optical detector
  4. optical switch

32. For a multimode optical graded index fiber, the profile parameter (α) will be equal to:

Answers:

  1. Zero
  2. 1
  3. 2

33. What would the optical return loss (ORL) be defined as when r-fresnal reflection occurs at a fiber-air interface?

Answers:

  1. ORL= -10log10r
  2. ORL= -20log10r
  3. ORL= -30log10r
  4. ORL= -10loger

34. When microwave frequency rather than radio frequency subcarriers are employed, the strategy is usually referred to as ______.

Answers:

  1. Time division multiplexing
  2. Frequency division multiplexing
  3. Code-division multiplexing
  4. Subcarrier multiplexing (SCM)

35. FDDI can support a data rate of

Answers:

  1. 10 Mbps
  2. 10 Gbps
  3. 100 Mbps
  4. 1000 Mbps

36. Numerical aperture (NA) is related to the refractive indexes of core (n1) and cladding (n2) when,

Answers:

  1. a
  2. b
  3. c
  4. d

37. What does TPON stand for?

Answers:

  1. Telephony on a pure optical network
  2. Telephony on a plastic optical network
  3. Telephony on a polarized optical network
  4. Telephony on a passive optical network

38. Light emitting diodes (LED’s) are:

Answers:

  1. Monochromatic incoherent sources
  2. Monochromatic coherent sources
  3. Incandescent light sources
  4. None of the above

39. A multimode graded index fiber exhibits total pulse broadening of 0.2 µsec over a distance of 10Km. Estimate the maximum possible bandwidth assuming that there is no inter-symbol interference.

Answers:

  1. 5 MHZ
  2. 2.5 MHZ
  3. 10 MHZ
  4. 1 MHZ

40. Homodyne detection is used for _______.

Answers:

  1. incoherent systems
  2. incandescent systems
  3. coherent systems
  4. analog systems

41. Avalanche photodiodes are ________.

Answers:

  1. less sensitive than simple photodiodes
  2. more sensitive than simple photodiodes
  3. cheaper than simple photodiodes
  4. less complex in structure than simple photodiodes

42. Hydrogen absorption by optical fiber causes _______.

Answers:

  1. an increase in efficiency
  2. a decrease in optical fiber losses
  3. no effect
  4. an increase in optical fiber losses

43. For an ideal photo detector, the absorption coefficient must be ______.

Answers:

  1. low
  2. zero
  3. one
  4. large

44. Rayleigh scattering is a ________.

Answers:

  1. non-linear scattering
  2. differential scattering
  3. cumulative scattering
  4. linear scattering

45. FDDI is _______.

Answers:

  1. Fiber dual data interface
  2. Fiber distributed data interface
  3. Fiber dual data interchange
  4. Fiber distributed data interchange

46. Macro bending losses in optical fibers can be reduced by designing the fibers with ________.

Answers:

  1. a smaller refractive index difference
  2. a fiber glass
  3. a silica glass
  4. a larger refractive index difference

47. Metallic impurities are eliminated from optical fiber by:

Answers:

  1. Vapor axial deposition (VAD) method
  2. Modified chemical vapor deposition (MCVD)method
  3. Vapor-phase oxidation method
  4. Plasma-activated chemical vapor deposition (PCVD)method

48. The information carrying capacity of optical fibers is in the range of:

Answers:

  1. MHZ
  2. mHZ
  3. GHZ
  4. µHZ

49. The first generation optical fibers are fabricated from:

Answers:

  1. Silica
  2. Oxides
  3. Gallium aluminum arsenide alloys
  4. Plastic

50. The Nd:YAG LASER is a/an_______.

Answers:

  1. non semiconductor laser
  2. semiconductor laser
  3. injection laser
  4. directional laser

51. Optical time domain reflectometry (OTDR) is a/an ________.

Answers:

  1. attenuation measurement technique
  2. refractive index measurement technique
  3. field measurement technique
  4. core diameter measurement technique

52. What is the relationship between refractive index (n1) of core and refractive index (n2) of cladding for an optical fiber?

Answers:

  1. n1 < n2
  2. n1 = n2
  3. n1 < n2
  4. n1 > n2

53. SOLITON is a/an ______.

Answers:

  1. type of optical fiber
  2. optical source
  3. optical detector
  4. pulse traveling in optical fiber

54. What is signal attenuation in an optical fiber where P1=Input power and P0=Output power

Answers:

  1. a
  2. b
  3. c
  4. None of the above

55. Index optical fibers are sometimes referred to as:

Answers:

    • Homogenous core fibers
    • Heterogeneous core fibers
    • Long fibers
    • Short fibers

56. IEEE 802.5 is a/an ________.

Answers:

  1. Ethernet
  2. Token bus
  3. Token ring
  4. Token star

57. The cutback technique is a/an _______.

Answers:

  1. attenuation measurement technique
  2. refractive index measurement technique
  3. impurity measurement technique
  4. frequency measurement technique

58. The refractive index is defined as the ratio of ____________.

Answers:

  1. the velocity of light in a vacuum to the velocity of light in the medium
  2. the velocity of light in the medium to the velocity of sound in a vacuum
  3. the velocity of light in the medium to the velocity of light in a vacuum

59. The population inversion phenomenon in optical sources occurs when _________.

Answers:

  1. the population of atoms in the upper energy level is greater than in the lower energy level
  2. the population of atoms in the lower energy level is greater than in the upper energy level
  3. the population of atoms in the upper and lower energy levels is equal
  4. None of the above

60. Intermodal dispersion is less in a __________.

Answers:

  1. Multimode step index fiber
  2. Multimode graded index fiber
  3. Single mode step index fiber
  4. Single mode graded index fiber

61. The fiber gyroscope is an ______.

Answers:

  1. Intrinsic fiber sensor
  2. Interferometer fiber sensor
  3. Extrinsic fiber sensor
  4. Extinction fiber sensor

62. One polarization maintaining fiber operates at a wavelength of 1.5 µm and has a beat length of 0.6mm. Its modal birefringence is given by _______.

Answers:

  1. 1.5 x 10-3
  2. 3.5 x 10-3
  3. 2.5 x 10-3
  4. 4.5 x 10-3

63. The output power of a LASER is greater than that of a LED because of _____.

Answers:

  1. stimulated emission
  2. spontaneous emission
  3. straight emission
  4. None of the above

64. Dispersion is low in the __________.

Answers:

  1. Multimode step index fiber
  2. Single mode step index fiber
  3. Two mode step index fiber
  4. None of the above

65. Surface emitter LEDs have high radiance because _______.

Answers:

  1. a hemisphere of n type GaAs is formed around a diffused p-type region
  2. of p-type diffusion into the n-type substrate
  3. it restricts the emission to a small active region
  4. of n-type diffusion into the p-type substrate

66. LASER stands for:

Answers:

  1. Light amplification by spontaneous emission of radiation
  2. Light amplification by stimulated emission of radiation
  3. Light amplification by straight emission of radiation
  4. None of the above

67. Dark line defects (DLDs) occur when:

Answers:

  1. non-radiative electron-hole recombination occurs
  2. mobile impurities are displaced into the active region of LASER
  3. all modes are not stabilized
  4. all modes are not polarized

68. Germanium avalanche photodiodes can be used for _______.

Answers:

  1. longer wavelength operation
  2. shorter wavelength operation
  3. low output power operation
  4. minimum noise operation

69. Which of the following is a characteristic of an injection LASER?

Answers:

  1. Frequency Chirp
  2. Amplification
  3. Frequency modulation
  4. Output power

942 total views, 2 views today

Upwork Electronics

Electronic Design Test 2016

Published by:

1. A Colpitt’s oscillator uses _____.

Answers:

  1. a tapped inductor
  2. a tapped capacitor
  3. no tapped inductor or capacitor
  4. both a tapped inductor and a tapped capacitor

2. A Wien-bridge oscillator is basically a _____.

Answers:

  1. pulse generator
  2. sine-wave generator
  3. square-wave generator
  4. triangular wave generator

3. A voltage V=300cos100t is applied to a half wave rectifier with RL =5KΩ. The rectifier may be represented by an ideal diode in series with a resistance of 1KΩ. What would be the ripple factor in this case?

Answers:

  1. 0
  2. 100%
  3. 110.21%
  4. 121.13%

4. A bridge rectifier circuit has secondary voltage of 12Vr.m.s. Assume secondary resistance and diode forward resistance to be negligible. The load resistance is 100Ω. What would be the peak load current?

Answers:

  1. 0.169 Amp
  2. 0.108 Amp
  3. 0.118 Amp
  4. 11.8 Amp

5. A half wave rectifier supplies power to 1000Ω load from a 110V (r.m.s) source of supply. If the forward resistance of the diode is 20Ω. What would be the efficiency of the rectifier?

Answers:

  1. 50%
  2. 25.73%
  3. 39.73%
  4. 30.11%

6. After triggering an SCR , the gate pulse is removed. the current in the SCR will _____.

Answers:

  1. remain the same
  2. immediately fall to zero
  3. rise-up
  4. rise a little and fall to zero

7. A feedback amplifier has an internal gain = 40dB and a feedback factor = 0.05, if the input impedance of this circuit is 12KΩ. What would have been the input impedance of the amplifier if the feedback had not been present?

Answers:

  1. 1KΩ
  2. 2KΩ
  3. 3KΩ
  4. 4KΩ

8. An amplifier has a gain of 10 without feedback. To make it oscillate, ß must be _____.

Answers:

  1. 0.2
  2. 0.1
  3. 0.5
  4. 0.8

9. For designing a Push-Pull amplifier, the type of transistors should be _____.

Answers:

  1. one should be p-n-p and the other should be n-p-n
  2. Both should be either p-n-p or n-p-n
  3. both should be n-p-n only
  4. All of the above

10. A crystal oscillator provides very stable frequency because of _____.

Answers:

  1. the high stability of the crystal
  2. the rigid crystal structure
  3. the low XL/R ratio of the crystal
  4. the high Q of the crystal

11. A transistor is a semiconductor switch which is _____.

Answers:

  1. unilateral and astable
  2. bilateral and astable
  3. unilateral and bistable
  4. bilateral and bistable

12. An Emitter follower is used for _____.

Answers:

  1. high current gain
  2. high voltage gain
  3. impedance matching
  4. high power gain

13. An amplifier has a bandwidth of 200KHz and a voltage gain of 100. What will be the new bandwidth if 5% negative feedback is introduced?

Answers:

  1. 1000KHz
  2. 1200KHz
  3. 1600KHz
  4. 2000KHz

14. A differentiator converts a linear ramp into a _____.

Answers:

  1. triangular wave
  2. square wave
  3. sinusoidal wave
  4. constant D.C signal

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