2. In an npn transistor, the majority carriers in the emitter are
Correct : A. free electrons
3. The barrier potential across each silicon depletion layer is
Correct : C. 0.7v
4. The base of an npn transistor is thin and
Correct : B. lightly doped
5. The emitter of a transistor is generally doped the heaviest because it
Correct : A. has to dissipate maximum power
6. When a transistor is fully switched ON, it is said to be
Correct : B. saturated
7. A FET consists of a
Correct : D. all the above
8. The extremely high input impedance of a MOSFET is primarily due to the
Correct : D. extremely small leakage current of its gate capacitor
9. When a transistor is used as a switch, it is stable in which two distinct regions?
Correct : C. saturation and cutoff
10. The term BJT is short for
Correct : D. bipolar junction transistor
11. What are the two types of bipolar junction transistors?
Correct : A. npn and pnp
12. The magnitude of dark current in a phototransistor usually falls in what range?
Correct : C. na
13. Junction Field Effect Transistors (JFET) contain how many diodes?
Correct : D. 1
14. When not in use, MOSFET pins are kept at the same potential through the use of:
Correct : C. conductive foam
15. A MOSFET has how many terminals?
Correct : D. 3 or 4
16. A very simple bias for a D-MOSFET is called:
Correct : C. zero biasing
17. Hybrid means
Correct : A. mixed
18. There are h- parameters of a transistor.
Correct : B. four
19. The h- parameter approach gives correct results for
Correct : B. small signals only
20. If the operating point changes, the h-parameters of transistor
Correct : A. also change
21. The dc load line on a family of collector characteristic curves of a transistor shows the
Correct : D. all of the above
22. When a transistor is used as a switch, it is stable in which two distinct regions?
Correct : C. saturation and cutoff
23. The value of βDC
Correct : D. varies with temperature and ic.
24. A BJT has an IB of 50 µA and a βDC of 75; IC is:
Correct : C. 3.75 ma
25. A certain transistor has IC = 15 mA and IB = 167 µA; βDC is:
Correct : D. 90
26. For normal operation of a pnp BJT, the base must be with respect to the emitter and with respect to the collector.
Correct : C. negative, positive
27. A transistor amplifier has a voltage gain of 100. If the input voltage is 75 mV, the output voltage is:
Correct : B. 7.5 v
28. A 35 mV signal is applied to the base of a properly biased transistor with an r'e = 8 Ω and RC = 1 kΩ. The output signal voltage at the collector is:
Correct : C. 4.375 v
29. What is the order of doping, from heavily to lightly doped, for each region?
Correct : B. emitter, collector, base
30. Which of the following is true for an npn or pnp transistor?
Correct : A. ie = ib + ic
31. In what range of voltages is the transistor in the linear region of its operation?
Correct : B. 0.7 < vce < vce(max)
32. What does DC vary with?
Correct : C. both ic and ºc
33. What is (are) common fault(s) in a BJT-based circuit?
Correct : D. all of the above
34. What is (are) general-purpose/small-signal transistors case type(s)?
Correct : D. all of the above
35. The magnitude of dark current in a phototransistor usually falls in what range?
Correct : C. na
36. Which of the following devices has the highest input resistance?
Correct : C. mosfet
37. A self-biased n-channel JFET has a VD = 6 V. VGS = –3 V. Find the value of VDS.
Correct : B. –6 v
38. A JFET data sheet specifies VGS(off) = –6 V and IDSS = 8 mA. Find the value of ID when VGS = –3 V.
Correct : A. 2 ma
39. A JFET data sheet specifies VGS(off) = –10 V and IDSS = 8 mA. Find the value of ID when VGS = –3 V.
Correct : D. 3.92 ma
40. The JFET is always operated with the gate-source pn junction
-biased.
Correct : B. reverse
41. What type(s) of gate-to-source voltage(s) can a depletion MOSFET (D-MOSFET) operate with?
Correct : D. any of the above
42. The has a physical channel between the drain and source.
Correct : A. d-mosfet
43. All MOSFETs are subject to damage from electrostatic discharge (ESD).
Correct : A. true
44. Midpoint bias for a D-MOSFET is ID = , obtained by setting VGS = 0.
Correct : C. idss
45. If VD is less than expected (normal) for a self-biased JFET circuit, then it could be caused by a(n)
Correct : D. all of the above
46. A coupling capacitor is
Correct : C. a dc open and an ac short
47. In a bypass circuit, the top of a capacitor is
Correct : C. an ac ground
48. The capacitor that produces an ac ground is called a
Correct : A. bypass capacitor
49. The output voltage of a CE amplifier is
Correct : D. all of the above
50. A common-gate amplifier is similar in configuration to which BJT amplifier?
Correct : C. common-base
51. A common-source amplifier is similar in configuration to which BJT amplifier?
Correct : C. common-emitter
52. When transistors are used in digital circuits they usually operate in the
Correct : C. saturation and cutoff regions
53. Which of the following elements are important in determining the gain of the system in the high-frequency region?
Correct : D. all of the above
54. For audio systems, the reference level is generally accepted as
.
Correct : A. 1 mw
55. What is the normalized gain expressed in dB for the cutoff frequencies?
Correct : A. –3 db
56. Which of the following configurations does not involve the Miller effect capacitance?
Correct : B. common-base
57. When transistors are used in digital circuits they usually operate in the
Correct : B. saturation and cutoff regions
58. A current ratio of IC/IE is usually less than one and is called
Correct : D. alpha
59. A transistor may be used as a switching device or as a:
Correct : D. variable resistor
60. Most of the electrons in the base of an NPN transistor flow:
Correct : A. into the collector
61. The BJT is a device. The FET is a device.
Correct : B. bipolar, unipolar
62. The Bode plot is applicable to
Correct : B. minimum phase network
63. For any inverting amplifier, the impedance capacitance will be
by a Miller effect capacitance sensitive to the gain of the amplifier and the interelectrode capacitance.
Correct : C. decreased
64. The dc emitter current of a transistor is 8 mA. What is the value of re?
Correct : C. 3.125 Ω
65. An emitter-follower amplifier has an input impedance of 107 kΩ. The input signal is 12 mV. The approximate output voltage is (common-collector)
Correct : C. 12 mv
66. You have a need to apply an amplifier with a very high power gain. Which of the following would you choose?
Correct : C. common-emitter
67. What is the most important r parameter for amplifier analysis?
Correct : C. re′
68. A common-emitter amplifier has voltage gain, current gain, power gain, and input impedance.
Correct : B. high, high, high, low
69. To analyze the common-emitter amplifier, what must be done to determine the dc equivalent circuit?
Correct : B. replace coupling and bypass capacitors with opens
70. What is re equal to in terms of h parameters?
Correct : A. hre / hoe
71. The advantage that a Sziklai pair has over a Darlington pair is
Correct : B. less input voltage is needed to turn it on.
72. What is the device in a transistor oscillator?
Correct : C. transistor
73. When the collector supply is 5V, then collector cut off voltage under dc condition is
Correct : D. 5 v
74. The common base (CB) amplifier has a compared to CE and CC amplifier.
Correct : A. lower input resistance
75. When a FET with a lower transconductance is substituted into a FET amplifier circuit, what happens?
Correct : B. the voltage gain decreases
76. At zero signal condition, a transistor sees load.
Correct : A. dc
77. What is the gain of an amplifier with negative feedback if the feedback factor is 0.01?
Correct : C. 100
78. The current gain of an emitter follower is
Correct : C. less than 1
79. The current in any branch of a transistor amplifier that is operating is
Correct : B. the sum of ac and dc
80. An ideal differential amplifiers common mode rejection ratio is
Correct : A. infinite
81. An open fuse circuit has a resistance equal to
Correct : D. infinity
82. What is the purpose of dc conditions in a transistor?
Correct : C. to set up operating point
83. The ac variations at the output side of power supply circuits are called .
Correct : A. ripples
84. What is the purpose of the emitter capacitor?
Correct : C. to avoid drop in gain
85. A common emitter circuit is also called circuit.
Correct : A. grounded emitter
86. The output signal of a common-collector amplifier is always
Correct : B. in phase with the input signal
87. Calculate the ripples of the filter output if a dc and ac voltmeter is used and measures the output signal from a filter circuit of 25 VDC and 1.5 Vrms
Correct : D. 6%
88. What is the ideal maximum voltage gain of a common collector amplifier?
Correct : A. unity
89. The output power of a transistor amplifier is more than the input power due to additional power supplied by
Correct : B. collector supply
90. When a transistor amplifier feeds a load of low resistance, its voltage gain will be
Correct : A. low
91. The capacitors are considered in the ac equivalent circuit of a transistor amplifier.
Correct : C. short
92. For highest power gain, what configuration is used?
Correct : C. ce
93. What is the most important characteristic of a common collector amplifier?
Correct : B. high input resistance
94. Which of the item below does not describe a common emitter amplifier?
Correct : D. high input resistance
95. CC configuration is used for impedance matching because its
Correct : A. input impedance is very high
96. Which of the following is the other name of the output stage in an amplifier?
Correct : C. power stage
97. When amplifiers are cascaded
Correct : C. the overall gain is increased
98. Ina common emitter amplifier, the capacitor from emitter to ground is called the
Correct : B. bypass capacitor
99. A class A power amplifier uses transistor(s).
Correct : B. one
100. What is the maximum collector efficiency of a resistance loaded class A power amplifier?