McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Electronics and Communication Engineering .
| 51. |
A common-source amplifier is similar in configuration to which BJT amplifier? |
| A. | common-base |
| B. | common- collector |
| C. | common-emitter |
| D. | emitter- follower |
| Answer» C. common-emitter | |
| 52. |
When transistors are used in digital circuits they usually operate in the |
| A. | active region |
| B. | breakdown region |
| C. | saturation and cutoff regions |
| D. | linear region |
| Answer» 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? |
| A. | interelectrode capacitances |
| B. | wiring capacitances |
| C. | miller effect capacitance |
| D. | all of the above |
| Answer» D. all of the above | |
| 54. |
For audio systems, the reference level is generally accepted as . |
| A. | 1 mw |
| B. | 1 w |
| C. | 10 mw |
| D. | 100 mw |
| Answer» A. 1 mw | |
| 55. |
What is the normalized gain expressed in dB for the cutoff frequencies? |
| A. | –3 db |
| B. | +3 db |
| C. | –6 db |
| D. | –20 db |
| Answer» A. –3 db | |
| 56. |
Which of the following configurations does not involve the Miller effect capacitance? |
| A. | common-emitter |
| B. | common-base |
| C. | common- collector |
| D. | all of the above |
| Answer» B. common-base | |
| 57. |
When transistors are used in digital circuits they usually operate in the |
| A. | active region |
| B. | saturation and cutoff regions |
| C. | breakdown region |
| D. | linear region |
| Answer» B. saturation and cutoff regions | |
| 58. |
A current ratio of IC/IE is usually less than one and is called |
| A. | omega |
| B. | beta |
| C. | theta |
| D. | alpha |
| Answer» D. alpha | |
| 59. |
A transistor may be used as a switching device or as a: |
| A. | tuning device |
| B. | rectifier |
| C. | fixed resistor |
| D. | variable resistor |
| Answer» D. variable resistor | |
| 60. |
Most of the electrons in the base of an NPN transistor flow: |
| A. | into the collector |
| B. | into the emitter |
| C. | out of the base lead |
| D. | into the base supply |
| Answer» A. into the collector | |
| 61. |
The BJT is a device. The FET is a device. |
| A. | bipolar, bipolar |
| B. | bipolar, unipolar |
| C. | unipolar, bipolar |
| D. | unipolar, unipolar |
| Answer» B. bipolar, unipolar | |
| 62. |
The Bode plot is applicable to |
| A. | all phase network |
| B. | minimum phase network |
| C. | maximum phase network |
| D. | lag lead network |
| Answer» 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. |
| A. | unaffected |
| B. | increased |
| C. | decreased |
| D. | none of the above |
| Answer» C. decreased | |
| 64. |
The dc emitter current of a transistor is 8 mA. What is the value of re? |
| A. | 320 Ω |
| B. | 13.3 kΩ |
| C. | 3.125 Ω |
| D. | 5.75 Ω |
| Answer» 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) |
| A. | 8.92 v |
| B. | 112 mv |
| C. | 12 mv |
| D. | 8.9 mv |
| Answer» 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? |
| A. | common-collector |
| B. | common-base |
| C. | common-emitter |
| D. | emitter- follower |
| Answer» C. common-emitter | |
| 67. |
What is the most important r parameter for amplifier analysis? |
| A. | rb′ |
| B. | rc′ |
| C. | re′ |
| D. | none of the above |
| Answer» C. re′ | |
| 68. |
A common-emitter amplifier has voltage gain, current gain, power gain, and input impedance. |
| A. | high, low, high, low |
| B. | high, high, high, low |
| C. | high, high, high, high |
| D. | low, low, low, high |
| Answer» B. high, high, high, low | |
| 69. |
To analyze the common-emitter amplifier, what must be done to determine the dc equivalent circuit? |
| A. | leave circuit unchanged |
| B. | replace coupling and bypass capacitors with opens |
| C. | replace coupling and bypass capacitors with shorts |
| D. | replace vcc with ground |
| Answer» B. replace coupling and bypass capacitors with opens | |
| 70. |
What is re equal to in terms of h parameters? |
| A. | hre / hoe |
| B. | (hre + 1) / hoe |
| C. | hie – (hre / hoe)(1 + hfe) |
| D. | hfe |
| Answer» A. hre / hoe | |
| 71. |
The advantage that a Sziklai pair has over a Darlington pair is |
| A. | higher current gain. |
| B. | less input voltage is needed to turn it on. |
| C. | higher input impedance. |
| D. | higher voltage gain. |
| Answer» B. less input voltage is needed to turn it on. | |
| 72. |
What is the device in a transistor oscillator? |
| A. | lc tank circuit |
| B. | biasing circuit |
| C. | transistor |
| D. | feedback circuit |
| Answer» C. transistor | |
| 73. |
When the collector supply is 5V, then collector cut off voltage under dc condition is |
| A. | 20 v |
| B. | 10 v |
| C. | 2.5 v |
| D. | 5 v |
| Answer» D. 5 v | |
| 74. |
The common base (CB) amplifier has a compared to CE and CC amplifier. |
| A. | lower input resistance |
| B. | larger current gain |
| C. | larger voltage gain |
| D. | higher input resistance |
| Answer» A. lower input resistance | |
| 75. |
When a FET with a lower transconductance is substituted into a FET amplifier circuit, what happens? |
| A. | the current gain does not change |
| B. | the voltage gain decreases |
| C. | the circuit disamplifies |
| D. | the input resistance decreases |
| Answer» B. the voltage gain decreases | |
| 76. |
At zero signal condition, a transistor sees load. |
| A. | dc |
| B. | ac |
| C. | both dc and ac |
| D. | resistive |
| Answer» A. dc | |
| 77. |
What is the gain of an amplifier with negative feedback if the feedback factor is 0.01? |
| A. | 10 |
| B. | 1000 |
| C. | 100 |
| D. | 500 |
| Answer» C. 100 | |
| 78. |
The current gain of an emitter follower is |
| A. | equal to 1 |
| B. | greater than 1 |
| C. | less than 1 |
| D. | zero |
| Answer» C. less than 1 | |
| 79. |
The current in any branch of a transistor amplifier that is operating is |
| A. | ac only |
| B. | the sum of ac and dc |
| C. | the difference of ac and dc |
| D. | dc only |
| Answer» B. the sum of ac and dc | |
| 80. |
An ideal differential amplifiers common mode rejection ratio is |
| A. | infinite |
| B. | zero |
| C. | unity |
| D. | undetermined |
| Answer» A. infinite | |
| 81. |
An open fuse circuit has a resistance equal to |
| A. | zero |
| B. | unity |
| C. | at least 100Ω at standard |
| D. | infinity |
| Answer» D. infinity | |
| 82. |
What is the purpose of dc conditions in a transistor? |
| A. | to reverse bias the emitter |
| B. | to forward bias the emitter |
| C. | to set up operating point |
| D. | to turn on the transistor |
| Answer» C. to set up operating point | |
| 83. |
The ac variations at the output side of power supply circuits are called . |
| A. | ripples |
| B. | pulses |
| C. | waves |
| D. | filters |
| Answer» A. ripples | |
| 84. |
What is the purpose of the emitter capacitor? |
| A. | to forward bias the emitter |
| B. | to reduce noise in the amplifier |
| C. | to avoid drop in gain |
| D. | to stabilize emitter voltage |
| Answer» C. to avoid drop in gain | |
| 85. |
A common emitter circuit is also called circuit. |
| A. | grounded emitter |
| B. | grounded collector |
| C. | grounded base |
| D. | emitter follower |
| Answer» A. grounded emitter | |
| 86. |
The output signal of a common-collector amplifier is always |
| A. | larger than the input signal |
| B. | in phase with the input signal |
| C. | out of phase with the input signal |
| D. | exactly equal to the input signal |
| Answer» 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 |
| A. | 5% |
| B. | 10% |
| C. | 50% |
| D. | 6% |
| Answer» D. 6% | |
| 88. |
What is the ideal maximum voltage gain of a common collector amplifier? |
| A. | unity |
| B. | infinite |
| C. | indeterminate |
| D. | zero |
| Answer» A. unity | |
| 89. |
The output power of a transistor amplifier is more than the input power due to additional power supplied by |
| A. | transistor |
| B. | collector supply |
| C. | emitter supply |
| D. | base supply |
| Answer» B. collector supply | |
| 90. |
When a transistor amplifier feeds a load of low resistance, its voltage gain will be |
| A. | low |
| B. | very high |
| C. | high |
| D. | moderate |
| Answer» A. low | |
| 91. |
The capacitors are considered in the ac equivalent circuit of a transistor amplifier. |
| A. | open |
| B. | partially open |
| C. | short |
| D. | partially short |
| Answer» C. short | |
| 92. |
For highest power gain, what configuration is used? |
| A. | cc |
| B. | cb |
| C. | ce |
| D. | cs |
| Answer» C. ce | |
| 93. |
What is the most important characteristic of a common collector amplifier? |
| A. | high input voltage |
| B. | high input resistance |
| C. | high output resistance |
| D. | its being an amplifier circuit |
| Answer» B. high input resistance | |
| 94. |
Which of the item below does not describe a common emitter amplifier? |
| A. | high voltage gain |
| B. | high current gain |
| C. | very high power gain |
| D. | high input resistance |
| Answer» D. high input resistance | |
| 95. |
CC configuration is used for impedance matching because its |
| A. | input impedance is very high |
| B. | input impedance is very low |
| C. | output impedance is very low |
| D. | output impedance is zero |
| Answer» A. input impedance is very high | |
| 96. |
Which of the following is the other name of the output stage in an amplifier? |
| A. | load stage |
| B. | audio stage |
| C. | power stage |
| D. | rf stage |
| Answer» C. power stage | |
| 97. |
When amplifiers are cascaded |
| A. | the gain of each amplifier is increased |
| B. | a lower supply voltage is required |
| C. | the overall gain is increased |
| D. | each amplifier has to work less |
| Answer» C. the overall gain is increased | |
| 98. |
Ina common emitter amplifier, the capacitor from emitter to ground is called the |
| A. | coupling capacitor |
| B. | bypass capacitor |
| C. | decoupling capacitor |
| D. | tuning capacitor |
| Answer» B. bypass capacitor | |
| 99. |
A class A power amplifier uses transistor(s). |
| A. | two |
| B. | one |
| C. | three |
| D. | four |
| Answer» B. one | |
| 100. |
What is the maximum collector efficiency of a resistance loaded class A power amplifier? |
| A. | 50% |
| B. | 78.50% |
| C. | 25% |
| D. | 30% |
| Answer» C. 25% | |
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