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BJT MALVINO Flashcards

1
Q
  1. A transistor has how many doped regions?
    a. 1
    b. 2
    c. 3
    d. 4
A

c. 3

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2
Q
  1. What is one important thing transistors do?
    a. Amplify weak signals
    b. Rectify line voltage
    C. Regulate voltage
    d. Emit light
A

a. Amplify weak signals

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3
Q
  1. Who invented the first junction transistor?
    a. Bell
    b. Faraday
    c. Marconi
    d. Shockley
A

d. Shockley

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4
Q
  1. In an npn transistor, the majority carriers in the base
    are
    a. Free electrons
    b. Holes
    c. Neither
    d. Both
A

a. Free electrons

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5
Q
  1. The barrier potential across each silicon depletion layer is
    a. 0
    b. 0.3 V
    c. 0.7 V
    d. 1 V
A

c. 0.7 V

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6
Q
  1. The emitter diode is usually
    a. Forward-biased
    b. Reverse-biased
    c. Nonconducting
    d. Operating in the breakdown region
A

a. Forward-biased

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7
Q
  1. For normal operation of the transistor, the collector diode has to be
    a Forward biased
    b. Reverse-biased
    c. Nonconducted
    d. Operating in the breakdown region
A

b. Reverse-biased

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8
Q
  1. The base of an npn transistor is thin and
    a. Heavily doped
    b. Lightly doped
    c. Metallic
    d. Doped by a pentavalent material
A

b. Lightly doped

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9
Q
  1. Most of the electrons in the base of an npn transistor flow
    a Out o the Base lead
    b. Into the collector
    c. into the emitter
    D. Into the base supply
A

b. Into the collector

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10
Q
  1. Most of the electrons in the base of an npn transistor
    do not recombine because they
    a. Have a long lifetime
    b. Have a negative charge
    c. Must flow through the base
    d. Flow out of the base
A

a. Have a long lifetime

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11
Q
  1. Most of the electrons that flow through the base will
    a. Flow into the collector
    D. Flow out of the base lead
    c. Recombine with base holes
    d. Recombine with collector holes
A

a. Flow into the collector

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12
Q
  1. The current gain of a transistor is the ratio of the
    a. Collector current to emitter current
    b. Collector current to base current
    c. Base current to collector current
    d. Emitter current to collector current
A

b. Collector current to base current

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13
Q
  1. Increasing the collector supply voltage will increase
    a. base current
    b. Collector current
    c. emitter current
    d. None of the above
A

d. None of the above

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14
Q
  1. The fact that only a few holes are in the base region means the base is
    a. Lightly doped
    b. Heavily doped
    c. undoped
    d. None of the above
A

a. Lightly doped

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15
Q
  1. in a normally biased npn tansistor, the electrons in the emitter have enough energy to overcome the barrier potential of the
    a. Base-emitter junction
    B. Base-collector junction
    c. Collector-base junction
    d. recombination path
A

a. Base-emitter junction

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16
Q
  1. When a free electron recombines with a hole in the base region, the free electron becomes
    a. Another tree electron
    b. A valence electron
    c. A conduction-band electron
    d. A majority carrier
A

b. A valence electron

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17
Q
  1. What is the most important fact about the collector
    current?
    a. It is measured in millimeters.
    b. It equals the base current divided by the current gain
    c. It is small
    d. It approximately equals the emitter current.
A

d. It approximately equals the emitter current.

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18
Q
  1. If the current gain is 200 and the collector current is
    101 mA the base current is
    a. 0.5 mA
    B. 2 MA
    c 2А
    D. 20 A
A

a. 0.5 mA

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19
Q
  1. The base-emitter voltage is usually
    a. Less than the base supply voltage
    b. Equal to the base supply voltage
    c. More than the base supply voltage
    d. Cannot answer
A

a. Less than the base supply voltage

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20
Q

20 The collector-emitter voltage is usually
a. Less than the collector supply voltage
b. Equal to the collector supply voltage
c. More than the collector supply voltage
d. Cannot answer

A

a. Less than the collector supply voltage

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21
Q
  1. The power dissipated by a transistor approximately equals the collector current times
    a. Base-emitter voltage
    b. Collector-emitter voltage
    c. Base supply voltage
    d. 0.7 V
A

b. Collector-emitter voltage

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22
Q
  1. A small collector current with zero base current is caused by the leakage current of the
    a. Emitter diode
    b. Collector diode
    c. base diode
    d. Transistor
A

b. Collector diode

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23
Q
  1. A transistor acts like a diode and a
    a. voltage source
    D. current source
    c. Resistance
    d. Power supply
A

D. current source

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24
Q
  1. If the base current is 100 mA and the current gain is
    30, the collector current is
    a. 300 mA
    D. 3 A
    c. 3.33 A
    d. 10 A
A

D. 3 A

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25
Q
  1. The base-emitter voltage of an ideal transistor is
    a. 0
    b. 0.3 V
    c. 0.7 V
A

a. 0

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26
Q
  1. If you recalculate the collector-emitter voltage with the second approximation the answer will usually be
    a. Smaller than the ideal value
    B. same as the real value
    c. Larger than the ideal value
    D. Inaccurate
A

c. Larger than the ideal value

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27
Q
  1. In the active region, the collector current is not changed significantly by
    a. Base supply voltage
    B. Base current
    c. Current gain
    d. Collector resistance
A

d. Collector resistance

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28
Q
  1. The base-emitter voltage of the second approximation is
    a. 0
    b. 0.3 V
    c. 0.7 V
A

c. 0.7 V

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29
Q
  1. If the base resistor is open, what is the collector current?
    a. 0
    c. 2 mA
    d. 10 mA
A

a. 0

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30
Q
  1. The current gain of a transistor is defined as the ratio or the collector current to the
    a. Base current
    b. Emitter current
    c. Supply current
    d. Collector current
A

a. Base current

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31
Q
  1. The graph of current gain versus collector-current
    indicates that the current gain
    a. Is constant
    b. Varies slightly
    c. Varies significantly
    d. Equals the collector current divided by the base
    current
A

c. Varies significantly

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32
Q
  1. When the collector current increases, what does the current gain do?
    a Decreases
    b. Stays the same
    c. Increases
    d. Any of the above
A

d. Any of the above

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33
Q
  1. As the temperature increases, the current gain
    a Decreases
    b. Remains the same
    c Increases
    d. Can be any of the above
A

d. Can be any of the above

34
Q
  1. When the base resistor decreases, the collector voltage will probably
    a. Decrease
    b. Stay the same
    c. Increase
    d. Do all of the above
A

a. Decrease

35
Q
  1. If the base resistor is very small, the transistor will operate in the
    a. Cutoff region
    b. Active region
    c. saturation region
    d. Breakdown region
A

c. saturation region

36
Q
  1. Ignoring the bulk resistance of the collector diode, the collector-emitter saturation voltage is
    a. 0
    b. A few tenths of a volt
    c. 1 V
    d. Supply voltage
A

a. 0

37
Q
  1. Three different Q points are shown on a load line. The upper Q point represents the
    a. Minimum current gain
    b. Intermediate current gain
    c. Maximum current gain
    D. Cutoff point
A

c. Maximum current gain

38
Q
  1. If a transistor operates at the middle of the load line, an increase in the base resistance will move the Q point
    a. Down
    b.Up
    c. Nowhere
    d. Off the load line
A

a. Down

39
Q
  1. If a transistor operates at the middle of the load line, an increase in the current gain will move the Q point
    a. Down
    b. Up
    c. Nowhere
    d. Off the load line
A

b. Up

40
Q
  1. If the base supply voltage increases, the Q point
    a. Down
    b. Up
    c. Nowhere
    d. Off the load line
A

b. Up

41
Q
  1. Suppose the base resistor is open. The Q point will
    a. In the middle of the load line
    b. At the upper end of the load line
    C. At the lower end of the load line
    D .Off the load line
A

C. At the lower end of the load line

42
Q
  1. If the base supply voltage is disconnected, the collector-emitter voltage will equal
    a. 0 V
    b. 6 V
    c. 10.5 V
    d. Collector supply voltage
A

d. Collector supply voltage

43
Q
  1. If the base resistor is shorted, the transistor will probably be
    a. Saturated
    b. In cutoff
    c. Destroyed
A

c. Destroyed

44
Q
  1. If the collector resistor decreases to zero in a base-biased circuit, the load line will become
    a. Horizontal
    b. Vertical
    c. Useless
    d. Flat
A

b. Vertical

45
Q
  1. The collector current is 10 mA. If the current gain is
    100, the base current is
    a 1 microamp
    b. 10 microamp
    c. 100 microamp
    G. T MA
A

c. 100 microamp

46
Q
  1. The base current is 50 microamp. If the current gain is 125, the collector current is closest in value to
    a. 40 microamp
    b. 500 microamp
    C TMA
    d. 6 MA
A

d. 6 MA

47
Q
  1. When the Q point moves along the load line, the voltage increases when the collector current
    a. Decreases
    b. stays the same
    c Increases
    d. Does none of the above
A

a. Decreases

48
Q
  1. When there is no base current in a transistor switch, the output voltage from the transistor is
    a. Low
    b. High
    c. Unchanged
    d. Unknown
A

b. High

49
Q
  1. A circuit with a fixed emitter current is called
    a Base bias
    b. Emitter bias
    c. Transistor bias
    d. Two-supply bias
A

b. Emitter bias

50
Q
  1. The first step in analyzing emitter-based circuits is to find the
    a. Base current
    b. Emitter voltage
    c. Emitter current
    d. Collector current
A

c. Emitter current

51
Q
  1. If the current gain is unknown in an emitter-biased circuit, you cannot calculate the
    a. Emitter voltage
    b. Emitter current
    c. Collector current
    d. Base current
A

d. Base current

52
Q
  1. If the emitter resistor is open, the collector voltage is
    a. Low
    b. High
    c. Unchanged
    D. Unknown
A

b. High

53
Q
  1. If the collector resistor is open, the collector voltage is
    a. Low
    b. High
    c. Unchanged
    d. Unknown
A

a. Low

54
Q
  1. When the current gain increases from 50 to 300 in an emitter-biased circuit, the collector current
    a. Remains almost the same
    b. Decreases by a factor of 6
    c. Increases by a factor of 6
    d. Is zero
A

a. Remains almost the same

55
Q
  1. If the emitter resistance decreases, the collector
    voltage
    a. Decreases
    o. stays the same
    c. Increases
    d. Breaks down the transistor
A

a. Decreases

56
Q
  1. If the emitter resistance decreases, the
    a. Q point moves up
    b. Collector current decreases
    c. Q point stays where it Is
    d. Current gain increases
A

a. Q point moves up

57
Q
  1. For emitter bias, the voltage across the emitter resistor
    is the same as the voltage between the emitter and the
    a. Base
    b. Collector
    C. emitter
    d.Ground
A

d.Ground

58
Q
  1. For emitter bias, the voltage at the emitter Is 0.7 V less than the
    a. Base voltage
    b. Emitter voltage
    c. Collector voltage
    d. Ground voltage
A

a. Base voltage

59
Q
  1. With voltage-divider bias, the base voltage is
    a. Less than the base supply voltage
    b. Equal to the base supply voltage
    c. Greater than the base supply voltage
    d. Greater than the collector supply voltage
A

a. Less than the base supply voltage

60
Q
  1. VDB is noted for its
    a. Unstable collector voltage
    b. Varying emitter current
    c. Large base current
    d. Stable Q point
A

d. Stable Q point

61
Q
  1. With VDB, an increase in emitter resistance will
    a. Decrease the emitter voltage
    b. Decrease the collector voltage
    c. Increase the emitter voltage
    d. Decrease the emitter current
A

c. Increase the emitter voltage

62
Q
  1. VDB has a stable Q point like
    a. Base bias
    b. Emitter bias
    c. Collector-feedback bias
    d. Emitter-feedback bias
A

b. Emitter bias

63
Q
  1. VDB needs
    a. Only three resistors
    b. Only one supply
    c Precision resistors
    d. More resistors to work better
A

b. Only one supply

64
Q
  1. VDB normally operates in the
    a. Active region
    b. Cutoff region
    c. Saturation region
    d. Breakdown region
A

a. Active region

65
Q
  1. The collector voltage of a VDB circuit is not sensitive to changes in the
    a. Supply voltage
    b. emitter resistance
    c. Current gain
    d. Collector resistance
A

c. Current gain

66
Q
  1. If the emitter resistance increases in a VDB circuit, the collector voltage
    a. Decreases
    b. Stays the same
    c. Increases
    d. Doubles
A

c. Increases

67
Q
  1. Base bias is associated with
    a. Amplifiers
    b. Switching circuits
    c. Stable Q point
    d. Fixed emitter current
A

b. Switching circuits

68
Q
  1. If the emitter resistance doubles in a VDB circuit, the collector current will
    a. Double
    b. Drop in half
    c. Remain the same
    d. Increase
A

b. Drop in half

69
Q
  1. If the collector resistance increases in a VDB circuit, the collector voltage will
    a. Decrease
    b. Stay the same
    c. Increase
    d. Double
A

a. Decrease

70
Q
  1. The Q point of a VDB circuit is
    a. Hypersensitive to changes in current gain
    b. Somewhat sensitive to changes in current gain
    c. Almost totally insensitive to changes in current gain
    d. Greatly affected by temperature changes
A

c. Almost totally insensitive to changes in current gain

71
Q
  1. The base voltage of two-supply emitter bias (TSEB)
    IS
    a. 0.7 V
    b. Very large
    c. Near 0 V
    d. 1.3 V
A

c. Near 0 V

72
Q
  1. If the emitter resistance doubles with TSEB, the collector current will
    a. Drop in half
    o. Slav the same
    c. Double
    d. increase
A

a. Drop in half

73
Q
  1. If a splash of solder shorts the collector resistor of
    TSEB, the collector voltage will
    a. Drop to zero
    b. Equal the collector supply voltage
    c. Stay the same
    d. Double
A

b. Equal the collector supply voltage

74
Q
  1. If the emitter resistance increases with TSEB, the collector voltage will
    a. Decrease
    b. Stay the same
    C. Increase
    d. Equal the collector supply voltage
A

C. Increase

75
Q
  1. If the emitter resistor opens with TSEB, the collector voltage will
    a. Decrease
    c. Stay the same
    c. Increase slightly
    d. Equal the collector supply voltage
A

d. Equal the collector supply voltage

76
Q
  1. In TSEB, the base current must be very
    a. Small
    b. Large
    c. Unstable
    d. Stable
A

a. Small

77
Q
  1. The Q point of TSEB does not depend on the
    a. Emitter resistance
    b. Collector resistance
    c. Current gain
    d. Emitter voltage
A

c. Current gain

78
Q
  1. The majority carriers in the emitter of a pnp transistor
    a. Holes
    b. free electrons
    c. Trivalent atoms
    d. Pentavalent atoms
A

a. Holes

79
Q
  1. The current gain of a pnp transistor is
    a. The negative of the non current gain
    b. The collector current divided by the emitter current
    C. Near 0
    d. The ratio of collector current to base current
A

d. The ratio of collector current to base current

80
Q
  1. Which is the largest current in a npn transistor?
    a. Base current
    b. Emitter current
    c. Collector current
    d. None of these
A

b. Emitter current

81
Q

25 The currents of a pnp transistor are
a. Usually smaller than npn currents
b. opposite npn currents
c. Usually larger than npn currents
d. Negative

A

b. opposite npn currents

82
Q
  1. With pnp voltage-divider bias, you must use
    a. Negative power supplies
    B. Positive power supplies
    c. Resistors
    D. Ground
A

c. Resistors

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