In this article, we published the top 250 electronic circuits objective and answers for electrical and instrumentation engineers.
Electronic Circuits Objective Questions
The below list provides all the multiple-choice questions (MCQ) related to electronic circuits.
Answers are available at the bottom of the article.
1. Practically, the voltage gain of an amplifier is expressed
| A) | As a whole number |
| B) | In dB unit |
| C) | In volts unit |
| D) | As an absolute value |
2. If a transistor is operated in such a way that output current flows for 160 degrees of the input signal, then it is _____ operation.
| A) | Class B |
| B) | Class C |
| C) | Class A |
| D) | Class AB |
3. The voltage gain of a common collector configuration is
| A) | Zero |
| B) | Moderate |
| C) | Very high |
| D) | Unity |
4. The gain of an amplifier is expressed in dB units because
| A) | Calculations become easy |
| B) | It is the most appropriate unit |
| C) | It is a simple unit |
| D) | Human ear response is logarithmic |
5. What is the phase difference between voltage across collector load and signal voltage in a common emitter amplifier?
| A) | 180° |
| B) | 270° |
| C) | 0° |
| D) | 90° |
6. A pair of filter common on high fidelity system which separate audio frequency band signals into two separate groups, where one is fed to the tweeter and the other to the woofer is called
| A) | Equalizer |
| B) | Synthesizer |
| C) | Cross over network |
| D) | Hybrid |
7. Which is not a basic BJT amplifier configuration?
| A) | Common-base |
| B) | Common-drain |
| C) | Common-collector |
| D) | Common-emitter |
8. An amplifier with efficiency of 85% is likely to be
| A) | Class B |
| B) | Class A |
| C) | Class C |
| D) | Class AB |
9. Minimum interference with frequency response can be given by
| A) | Transformer coupling |
| B) | Instrumentation and control |
| C) | Direct coupling |
| D) | RC coupling |
10. The general characteristics of a common base amplifier are
| A) | None of the answers |
| B) | High voltage, high current gain, high power gain and low input resistance |
| C) | Low voltage gain, high current gain, very high power gain and low input resistance |
| D) | High voltage gain, low current gain, high power gain and very low input resistance |
11. When the collector resistor in a common emitter amplifier is increased in value the voltage gain
| A) | Becomes erratic |
| B) | None of the answers |
| C) | Increases |
| D) | Decreases |
12. Which of the following describes a common collector amplifier?
| A) | Low input resistance |
| B) | Low current gain |
| C) | Low voltage gain |
| D) | Low power gain |
13. What is the main consideration in the output stage of an amplifier?
| A) | Current gain |
| B) | Power output |
| C) | Power gain |
| D) | Voltage gain |
14. An oscillator employs ____ feedback.
| A) | Negative |
| B) | Positive |
| C) | Neither positive nor negative |
| D) | Both positive and negative |
15. What is the typical value of coupling capacitor Cc in RC coupling?
| A) | About 0.01µF |
| B) | About 0.1µF |
| C) | About 10µF |
| D) | About 100 pF |
16. A pulsating dc applied to power amplifiers causes
| A) | Hum in the circuit |
| B) | Excessive reverse voltage |
| C) | Burning of transistor |
| D) | Excessive forward voltage |
17. The final stage of an amplifier uses _____ coupling.
| A) | RC |
| B) | Transformer |
| C) | Impedance |
| D) | Direct |
18. A transistor converts
| A) | Ac power into dc power |
| B) | Low resistance into high resistance |
| C) | High resistance into low resistance |
| D) | Dc power into ac power |
19. Which frequency produces the highest noise factor?
| A) | 1kHz |
| B) | 10kHz |
| C) | 500Hz |
| D) | 100 Hz |
20. Which power amplifier has the highest collector efficiency?
| A) | Class B |
| B) | Class A |
| C) | Class AB |
| D) | Class C |
21. An LC oscillator cannot be used to produce ______ frequencies.
| A) | Very high |
| B) | High |
| C) | Audio |
| D) | Very low |
22. The number of stages that can be directly coupled is limited because
| A) | Circuit becomes heavily and costly |
| B) | Change in temperature can cause thermal instability |
| C) | It becomes difficult to bias the circuit |
| D) | Circuits’ resistance becomes too large |
23. Class C operation can have _____ percent efficiency.
| A) | 70% |
| B) | 78.5% |
| C) | 50% |
| D) | 100% |
24. What oscillator circuit uses a tapped coil in the tuned circuit?
| A) | Colpitts |
| B) | Hartley |
| C) | Pierce |
| D) | Crystal |
25. What is the most stable sine-wave oscillator which uses piezo-electric quartz crystal?
| A) | DC restorer |
| B) | Crystal oscillator |
| C) | Hartley and Colpitts oscillator |
| D) | Wien-bridge oscillator |
26. Class B operation has a maximum possible frequency of _____ percent.
| A) | 2.2% |
| B) | 78.5% |
| C) | 100% |
| D) | 75% |
27. In a phase shift oscillator, 180° phase-shift is obtained
| A) | A transformer |
| B) | Three LC sections |
| C) | LC tank circuit |
| D) | Three RC sections |
28. If the noise factor of an ideal amplifier is expressed in dB, then it is
| A) | 0 |
| B) | 10 |
| C) | 0.1 |
| D) | 1 |
29. Which transistor configuration offers no phase reversal at the output?
| A) | Common-collector |
| B) | Common-emitter |
| C) | Common-base |
| D) | Both Common-base & Common-collector |
30. Comparatively, power amplifier has ___ þ.
| A) | Small |
| B) | Very small |
| C) | Large |
| D) | Very large |
31. What linear circuit compares two input signals and provides a digital level output depending on the relationship of the input signals?
| A) | Controller |
| B) | Compressor |
| C) | Switch |
| D) | Comparator |
32. A tuned amplifier is used in what application?
| A) | Low frequency |
| B) | Radio frequency |
| C) | Intermediate frequency |
| D) | Audio frequency |
33. Which of the following is NOT an oscillator requirement?
| A) | Amplifier |
| B) | Feedback |
| C) | Tank circuit |
| D) | Attenuator |
34. To obtain the frequency response curve of an amplifier _____ is kept constant
| A) | Generator output level |
| B) | Amplifier output |
| C) | Generator frequency |
| D) | Amplifier frequency |
35. What is the reason why RC coupling is not used to amplify extremely low frequencies?
| A) | Electrical size of coupling capacitor becomes very small |
| B) | There is considerable power loss |
| C) | Electrical size of coupling capacitor becomes very large |
| D) | There is a hum in the output |
36. What is the purpose of the emitter capacitor?
| A) | To forward bias the emitter |
| B) | To reduce noise in the amplifier |
| C) | To stabilize emitter voltage |
| D) | To avoid drop in gain |
37. At zero signal condition, a transistor sees ____ load.
| A) | ac |
| B) | dc |
| C) | resistive |
| D) | both dc and ac |
38. In a class A amplifier, the output signal is
| A) | The same as the input |
| B) | Smaller in amplitude than the input |
| C) | Clipped |
| D) | Distorted |
39. What type of feedback is used in Wien bridge oscillator?
| A) | Negative |
| B) | Either positive or negative |
| C) | Both positive and negative |
| D) | Positive |
40. The gain of an amplifier with feedback is known as _____ gain.
| A) | Closed loop |
| B) | Unity |
| C) | Resonant |
| D) | Open loop |
41. The quiescent current of a FET amplifier is
| A) | Id |
| B) | id |
| C) | IDS |
| D) | ID |
42. The stability of a regulated power supply is equivalent to
| A) | product of the output voltage and supply voltage |
| B) | change of output voltage over the change in supply voltage |
| C) | change in supply voltage over the change of output voltage |
| D) | the difference of an output voltage to its supply voltage |
43. What is the advantage of RC coupling scheme?
| A) | Economy |
| B) | Good impedance matching |
| C) | Simplicity |
| D) | High efficiency |
44. What is the maximum collector efficiency of a transformer coupled class A power amplifier?
| A) | 30% |
| B) | 50% |
| C) | 80% |
| D) | 45% |
45. When the non-linear distortion in an amplifier is D without feedback, with negative voltage feedback it will be
| A) | 1+A β/ D |
| B) | D (1+A β) |
| C) | D (1-A β) |
| D) | D/ 1+A β |
46. Class C is an amplifier whose output current flows for
| A) | Twice the entire input cycle |
| B) | Less than one-half the entire input cycle |
| C) | Greater than one-half the entire input cycle |
| D) | The entire input cycle |
47. When amplifiers are cascaded
| A) | The gain of each amplifier is increased |
| B) | The overall gain is increased |
| C) | Each amplifier has to work less |
| D) | A lower supply voltage is required |
48. Which of the item below does not describe a common emitter amplifier?
| A) | High current gain |
| B) | High voltage gain |
| C) | Very high power gain |
| D) | High input resistance |
49. The bandwidth of an amplifier ____ when negative feedback is applied.
| A) | Becomes infinite |
| B) | Remains unchanged |
| C) | Increases |
| D) | Decreases |
50. When CE configuration is used for an oscillator, the voltage fed back must
| A) | Be taken from a capacitor |
| B) | Have a 0° phase shift |
| C) | Be inverted by 180° |
| D) | Taken from an inductor |
51. An AF transformer is shielded to
| A) | Prevent electric shock |
| B) | Protect from rusting |
| C) | Prevent the induction due to stray magnetic fields |
| D) | Keep the amplifier cool |
52. What type of oscillator which is composed of one or more amplifying devices with some frequency determining networks introducing positive feedback at a particular frequency so that oscillation is sustained at that frequency?
| A) | Limiter |
| B) | Relaxation oscillator |
| C) | Sine wave oscillator |
| D) | Square-wave generator |
53. What class of operation has little use in general purpose amplifiers, but is used in high frequency oscillators?
| A) | Class A |
| B) | Class C |
| C) | Class AB |
| D) | Class B |
54. A tuned amplifier uses what load?
| A) | LC tank |
| B) | Inductive |
| C) | Capacitive |
| D) | Resistive |
55. An ammeter’s ideal resistance should be
| A) | Infinite |
| B) | The same with the circuits resistance |
| C) | Unity |
| D) | Zero |
56. The output power of a transistor amplifier is more than the input power due to additional power supplied by
| A) | Collector supply |
| B) | Base supply |
| C) | Emitter supply |
| D) | Transistor |
57. The number of transistor in a single stage amplifier is
| A) | One |
| B) | Four |
| C) | Three |
| D) | Two |
58. Find the voltage drop developed across a D’ Arsonval meter movement having an internal resistance of 1 KΩ and a full deflection current of 150uA.
| A) | 150mV |
| B) | 150V |
| C) | 200mV |
| D) | 150µV |
59. AC load line has a/an _____ slope compared to that of dc load line.
| A) | Smaller |
| B) | Infinite |
| C) | Bigger |
| D) | Zero |
60. When shock-excited, a crystal will produce alternating emf longer than an LC circuit because
| A) | has fewer losses |
| B) | is very rigid |
| C) | is small-sized |
| D) | has greater mechanical strength |
61. Amplitude distortion is otherwise known as _____ distortion.
| A) | Intermodulation |
| B) | Phase |
| C) | Harmonic |
| D) | Resonant |
62. What is the typical value of the emitter bypass capacitor CE in a multistage amplifier?
| A) | About 100pF |
| B) | About 50µF |
| C) | About 0.01µF |
| D) | About 0.1µF |
63. The gain of an amplifier _____ when negative feedback is added.
| A) | Reduces |
| B) | Remains unchanged |
| C) | Becomes infinite |
| D) | Increases |
64. In transistor amplifiers, what transformer is used for impedance matching?
| A) | Step down |
| B) | Step up |
| C) | Isolation |
| D) | Power |
65. Oscillators operate on the principle of
| A) | Signal feedthrough |
| B) | Attenuation |
| C) | Negative feedback |
| D) | Positive feedback |
66. In phase-shift oscillator, what are the frequency determining elements?
| A) | R and C |
| B) | L and C |
| C) | R and L |
| D) | R, L and C |
67. When crystal frequency increases with temperature, it has _____ temperature co- efficient.
| A) | Infinite |
| B) | Positive |
| C) | Zero |
| D) | Negative |
68. The input resistance of a common emitter amplifier is affected by
| A) | Rc and re |
| B) | α and re |
| C) | β and re |
| D) | Re , re, and β |
69. If the capacitor from emitter to ground in a common emitter amplifier is removed, the voltage gain
| A) | Increases |
| B) | None of the answers |
| C) | Decreases |
| D) | Becomes erratic |
70. What is the time taken by the electrons or holes to pass from the emitter to the collector?
| A) | Transit time |
| B) | Duty cycle |
| C) | Transient time |
| D) | Recombination |
71. What is the gain of an amplifier with negative feedback if the feedback factor is 0.01?
| A) | 10 |
| B) | 100 |
| C) | 1,000 |
| D) | 500 |
72. Which amplifier whose output current flows for the entire cycle?
| A) | Class A |
| B) | Class C |
| C) | Class AB |
| D) | Class B |
73. Class A operation has a maximum possible efficiency of ______ percent.
| A) | 100% |
| B) | 75% |
| C) | 50% |
| D) | 25% |
74. The input impedance of an amplifier _____ when negative voltage feedback is applied.
| A) | Is unchanged |
| B) | Decreases |
| C) | Increases |
| D) | Becomes zero |
75. What is the desired input impedance of a transistor?
| A) | Very high |
| B) | Low |
| C) | Very low |
| D) | High |
76. Low efficiency of a power amplifier results in
| A) | Low power output |
| B) | Less battery consumption |
| C) | More battery consumption |
| D) | Low forward bias |
77. Transmit time is the time taken by the electrons on holes to pass from
| A) | Base to collector |
| B) | Base to emitter |
| C) | Emitter to collector |
| D) | Collector to emitter |
78. The common base (CB) amplifier has a ______ compared to CE and CC amplifier.
| A) | Lower input resistance |
| B) | Larger current gain |
| C) | Higher input resistance |
| D) | Larger voltage gain |
79. What happens if the input capacitor of a transistor amplifier is short-circuited?
| A) | Signal will not reach the base |
| B) | Transistor will be destroyed |
| C) | Biasing conditions will change |
| D) | Biasing will stabilize |
80. Which of the following is the other name of the output stage in an amplifier?
| A) | Load stage |
| B) | Audio stage |
| C) | RF stage |
| D) | Power stage |
81. The frequency stability of the oscillator output is maximum in _____ oscillator.
| A) | LC |
| B) | Phase-shift |
| C) | Wien bridge |
| D) | Crystal |
82. Transformer coupling is generally employed when load resistance is
| A) | Zero |
| B) | Large |
| C) | Very large |
| D) | Small |
83. What is the point of intersection of dc and ac load lines called?
| A) | Cut off point |
| B) | Saturation point |
| C) | Breakdown |
| D) | Operating point |
84. When negative current feedback is applied to an amplifier, its output impedance
| A) | remains unchanged |
| B) | decreases |
| C) | increases |
| D) | becomes zero |
85. Generally tuned amplifiers are operated in
| A) | Class A |
| B) | Class C |
| C) | Class B |
| D) | Class AB |
86. What is the purpose of capacitors in a transistor amplifier?
| A) | To provide biasing |
| B) | To couple or bypass ac component |
| C) | To cool the transistor |
| D) | To protect the transistor |
87. For constant- K high-pass filter cut-off frequency (in Hz) is given by
| A) | 1/(2π√LC) |
| B) | 1/(4π√LC) |
| C) | π/√LC |
| D) | 1 /(π√LC) |
88. Consider a zener diode with a slope resistance of 10Ω in series with a 90Ω resistor fed from a dc supply containing a ripple voltage of 20mV peak-to-peak.
Compute for the ripple voltage in load
| A) | 1 mV p-p |
| B) | 2 mV p-p |
| C) | 6mV p-p |
| D) | 1 V p-p |
89. The ac variations at the output side of power supply circuits are called .
| A) | Pulses |
| B) | Ripples |
| C) | Filters |
| D) | Waves |
90. Transformer coupling can be used in _____ amplifiers
| A) | Either power or voltage |
| B) | Only power |
| C) | Neither power nor voltage |
| D) | Only voltage |
91. Transformer coupling is used for _____ amplification.
| A) | Signal |
| B) | Power |
| C) | Voltage |
| D) | Current |
92. To sustain oscillations, the power gain of the amplifier may be
| A) | Infinite |
| B) | Any value form 0.5 upward |
| C) | Between 0.1 and 0.5 |
| D) | Equal to or greater than 1 |
93. The input capacitor in an amplifier is called _____ capacitor.
| A) | Stray |
| B) | Electrolytic |
| C) | Bypass |
| D) | Coupling |
94. Class C operation is preferred in oscillators because it
| A) | Gives larger outputs |
| B) | Produces square waves |
| C) | Is more efficient |
| D) | Increases stability |
95. In a multistage amplifier, if the stages have R and C component only, operation is apparent.
| A) | Class B |
| B) | Class C |
| C) | Class AB |
| D) | Class A |
96. Which operation gives the maximum distortion?
| A) | Class B |
| B) | Class A |
| C) | Class AB |
| D) | Class C |
97. The total decibel voltage gain of two cascaded voltage amplifier where individual voltage gains are 10 and 100 is
| A) | 1000 |
| B) | 20 |
| C) | 60 |
| D) | 800 |
98. For a constant output frequency, the simplest sinusoidal oscillator is the .
| A) | Phase-shift circuit |
| B) | Colpitts circuits |
| C) | Crystal oscillator |
| D) | Hartley circuit |
99. If you move towards an oscillating circuit, its frequency changes because of
| A) | Movement of the body |
| B) | Stray capacitance |
| C) | Noise of foot |
| D) | Hand capacitance |
100. The _____ of a common collector configuration is unity
| A) | Current gain |
| B) | Input impedance |
| C) | Power gain |
| D) | Voltage gain |
101. What type of coupling is generally used in power amplifiers?
| A) | Transformer |
| B) | RC |
| C) | Direct |
| D) | Inductive |
102. In a Colpitt’s oscillator, feedback is obtained
| A) | By a tickler coil |
| B) | From the center of split inductors |
| C) | From the center of split capacitors |
| D) | By magnetic induction |
103. What is the disadvantage of impedance matching?
| A) | It gives distorted output |
| B) | It requires a transformer |
| C) | It is expensive |
| D) | It gives low power output |
104. buffer amplifier is used for
| A) | Minimum loading and maximum mismatch |
| B) | Minimum loading and minimum mismatch |
| C) | Maximum loading and maximum mismatch |
| D) | Maximum loading and minimum mismatch |
105. In order to have more voltage gain from a transformer amplifier the transistor used should have
| A) | Thin base |
| B) | Thin emitter |
| C) | Wide emitter |
| D) | Thin collector |
106. The output transformer used in a power amplifier is a/an _____ transformer
| A) | Isolation |
| B) | Step-down |
| C) | Step-up |
| D) | 1:1 ratio |
107. Feedback circuit usually employs ______ network
| A) | Inductive |
| B) | Resistive |
| C) | Capacitive |
| D) | Active |
108. An ideal differential amplifiers common mode rejection ratio is
| A) | Zero |
| B) | Infinite |
| C) | Unity |
| D) | Undetermined |
109. A type of oscillator wherein the frequency is determined by the charge and discharge of resistor capacitor networks used in conjunction with amplifiers or similar devices.
| A) | Sine wave oscillator |
| B) | Relaxation oscillator |
| C) | Beta generating circuit |
| D) | Simply an oscillator |
110. When negative voltage feedback is applied to an amplifier, its output impedance
| A) | Increases |
| B) | Becomes zero |
| C) | Decreases |
| D) | Remains unchanged |
111. Hartley oscillator is commonly used in which of the following?
| A) | TV receivers |
| B) | Radio transmitters |
| C) | Radio receivers |
| D) | CATV |
112. Which is a fixed-frequency oscillator
| A) | Crystal oscillator |
| B) | Phase-shift oscillator |
| C) | Colpitt’s oscillator |
| D) | Hartley oscillator |
113. RC coupling is used for ______ amplification.
| A) | Power |
| B) | Current |
| C) | Voltage |
| D) | Signal |
114. A complementary-symmetry amplifier has
| A) | One PNP and one NPN transistor |
| B) | Two PNP and two NPN transistors |
| C) | Two PNP transistors |
| D) | Two NPN transistors |
115. The term 1+ A þ in the expression for gain with negative feedback is known as
| A) | Sacrifice factor |
| B) | Gain factor |
| C) | Feedback factor |
| D) | Quality factor |
116. In a common emitter amplifier, the capacitor from emitter to ground is called the
| A) | Tuning capacitor |
| B) | Coupling capacitor |
| C) | Decoupling capacitor |
| D) | Bypass capacitor |
117. What class of operation is used either where the signal needs to be cut in half, such as in pulse detector or noise detectors or where push-pull operation of two stages is required?
| A) | Class AB |
| B) | Class B |
| C) | Class A |
| D) | Class C |
118. What is the ideal maximum voltage gain of a common collector amplifier?
| A) | Zero |
| B) | Infinite |
| C) | Indeterminate |
| D) | Unity |
119. The capacitors are considered ______ in the ac equivalent circuit of a transistor amplifier.
| A) | Partially open |
| B) | Open |
| C) | Short |
| D) | Partially short |
120. Transformer coupling introduces what type of distortion?
| A) | Frequency |
| B) | Intermodulation |
| C) | Amplitude |
| D) | Phase |
121. What coupling provides maximum voltage gain?
| A) | Direct |
| B) | RC |
| C) | Transformer |
| D) | Resistor |
122. Which of the items below is not a description of the two-stage amplifier?
| A) | The input resistance is equal to the input resistance of the first stage unless feedback is applied |
| B) | Its output resistance is equal to the output resistance of the final stage unless feedback is applied |
| C) | The output resistance is equal to the output resistance of the first stage unless feedback is applied. |
| D) | Its noise level is equal to the accumulated noise of the two stages, either by multiplying the noise voltage amplitudes together or by adding the noise decibel levels together |
123. Increasing the overall Beta is an advantage of
| A) | Crystal oscillator |
| B) | Darlington pair |
| C) | Clap oscillator |
| D) | CE amplifier |
124. What is the purpose of dc conditions in a transistor?
| A) | To reverse bias the emitter |
| B) | To set up operating point |
| C) | To forward bias the emitter |
| D) | To turn on the transistor |
125. Which of the following is provided by a CB transistor amplifier?
| A) | Voltage gain |
| B) | Gain stability |
| C) | Power gain |
| D) | Current gain |
126. What is the phase difference between the output and the input voltage of a CE amplifier?
| A) | 90° |
| B) | 180° |
| C) | 0° |
| D) | 270° |
127. For highest power gain, what configuration is used?
| A) | CB |
| B) | CE |
| C) | CS |
| D) | CC |
128. An oscillator oscillates due to
| A) | Both positive and negative feedback |
| B) | Negative feedback |
| C) | Positive feedback |
| D) | Neither positive nor negative feedback |
129. What oscillator is used on order to produce frequencies in the microwave region?
| A) | Crystal |
| B) | Hartley |
| C) | Klystron |
| D) | Wien bridge |
130. What is the basic purpose of applying negative feedback to an amplifier?
| A) | To increase input signal |
| B) | To increase gain |
| C) | To reduce distortion |
| D) | To keep the temperature within limits |
131. Determine the attenuation in dB for a T-pad for which R1=R2= 40Ω and R3= 36Ω .
The pad connects a 50Ω generator to a 50Ω load.
| A) | 83.93 dB |
| B) | 11.93 dB |
| C) | 10.83 dB |
| D) | 9.83 dB |
132. What is the ratio of output to the input impedance of a CE amplifier?
| A) | Approximately 1 |
| B) | Moderate |
| C) | Very high |
| D) | Very low |
133. Which is used to establish a fixed level of current or voltage in a transistor?
| A) | Loading |
| B) | Load line |
| C) | Biasing |
| D) | Coupling |
134. What class of operation is used for general amplification where no distortion can be tolerated?
| A) | Class AB |
| B) | Class A |
| C) | Class C |
| D) | Class B |
135. The signal generator generally used in laboratories is _____ oscillator
| A) | Wien-bridge |
| B) | Hartley |
| C) | Phase-shift |
| D) | Crystal |
136. What is the axis that connects the corners of a crystal?
| A) | Mechanical |
| B) | X |
| C) | Y |
| D) | Z |
137. When the gain is 20 without feedback and 12 with negative feedback, feedback factor is
| A) | 5/3 |
| B) | 1/5 |
| C) | 0.033 |
| D) | 3/5 |
138. What circuit increases the peak–to–peak voltage, current or power of a signal?
| A) | Amplifier |
| B) | Power supply |
| C) | Attenuator |
| D) | Filter |
139. A multistage amplifier uses at least how many transistors?
| A) | Four |
| B) | One |
| C) | Three |
| D) | Two |
140. Emitter follower employs _____ negative feedback.
| A) | 100% |
| B) | 50% |
| C) | 25% |
| D) | 75% |
141. What is the purpose of RC or transformer coupling?
| A) | To increase thermal stability |
| B) | To block ac |
| C) | To block dc |
| D) | To separate bias of one stage from another |
142. What is the most important characteristic of a common collector amplifier?
| A) | High input voltage |
| B) | Its being an amplifier circuit |
| C) | High input resistance |
| D) | High output resistance |
143. The input impedance of which amplifier depends strongly on load resistance?
| A) | CB |
| B) | CC |
| C) | CE |
| D) | CD |
144. What application where one would most likely find a crystal oscillator?
| A) | AF generator |
| B) | Oscilloscope |
| C) | Radio receiver |
| D) | Radio transmitter |
145. The frequency response of the combined amplifier can be compared with
| A) | A positive filter |
| B) | A negative feedback amplifier |
| C) | An OR gate |
| D) | An AND gate |
146. The simplest variable frequency sinusoidal oscillator is the
| A) | Armstrong circuit |
| B) | Complicated Colpitts circuit |
| C) | Crystal circuit |
| D) | Phase shift circuit |
147. A common-emitter circuit is also called _____ circuit.
| A) | Emitter follower |
| B) | Grounded base |
| C) | Grounded collector |
| D) | Grounded emitter |
148. Logic analyzer is used to
| A) | To analyze the logic operation of the system |
| B) | To sample and display systems signal |
| C) | Verify the logic operation of the gates in a circuit |
| D) | To display the fall time |
149. The driver transformer has center-tapped secondary to provide
| A) | Forward bias to transistors of push-pull circuit |
| B) | Two signals in phase with each other |
| C) | Two signals 180 degrees out of phase to transistors of push-pull circuit |
| D) | Impedance matching |
150. In the initial stages of a multistage amplifier, ______ coupling is used.
| A) | RC |
| B) | Transformer |
| C) | Impedance |
| D) | Link |
151. Class C amplifiers are used as
| A) | IF amplifiers |
| B) | RF amplifiers |
| C) | AF amplifiers |
| D) | Small signal amplifiers |
152. The operating frequency of a Wien-bridge oscillator is given by
| A) | 1/(4πLC) |
| B) | 1/29RC |
| C) | 1/(2πLC) |
| D) | 1/(2πRC) |
153. A two-transistor class B power amplifier is commonly called
| A) | Dual amplifier |
| B) | Differential amplifier |
| C) | Symmetrical amplifier |
| D) | Push-pull amplifier |
154. What is the operating point in the characteristic curve called?
| A) | Saturation point |
| B) | Biasing point |
| C) | Quiescent point |
| D) | Load point |
155. Power amplifiers generally use transformer coupling because transformer coupling provides
| A) | Cooling of the circuit |
| B) | Good frequency response |
| C) | Distortionless output |
| D) | Impedance matching |
156. The ear is not sensitive to _____ distortion.
| A) | Phase |
| B) | Amplitude |
| C) | Frequency |
| D) | Harmonic |
157. A class A power amplifier uses _____ transistor(s).
| A) | Two |
| B) | One |
| C) | Four |
| D) | Three |
158. An emitter follower is equivalent to
| A) | Common base amplifier |
| B) | Hybrid connection |
| C) | Common emitter amplifier |
| D) | Common collector amplifier |
159. Feedback factor is always
| A) | Equal to 1 |
| B) | Zero |
| C) | Less than 1 |
| D) | More than 1 |
160. If gain without feedback and feedback factor are A and þ respectively, then gain with negative feedback is given by
| A) | (1+A β) A |
| B) | 1+A β / A |
| C) | A/ 1-A β |
| D) | A/ 1+ A β |
161. The voltage gain over mid- frequency range in an RC coupled amplifier
| A) | Changes instantly with frequency |
| B) | Is independent of the coupling |
| C) | Is constant |
| D) | Is maximum |
162. The bandwidth of a single stage amplifier is ______ that of multistage amplifier.
| A) | Less than |
| B) | More than |
| C) | Equal to |
| D) | Independent |
163. In an LC oscillator, if the value of L is increased four times, then the frequency of oscillation is
| A) | Increased 4 times |
| B) | Increased 2 times |
| C) | Decreased 2 times |
| D) | Decreased 4 times |
164. A feedback circuit is _____ frequency
| A) | Independent of |
| B) | Relatively dependent on |
| C) | Moderately dependent on |
| D) | Strongly dependent on |
165. Power amplifiers handle _____ signals.
| A) | Very small |
| B) | Very large |
| C) | Large |
| D) | Small |
166. Which of the following amplifier is considered linear?
| A) | Either Class A or B |
| B) | Class C |
| C) | Class A |
| D) | Class B |
167. Which configuration has the lowest current gain?
| A) | Common-collector |
| B) | Emitter follower |
| C) | Common-base |
| D) | Common-emitter |
168. The efficiency of class AB operation has a maximum of between _____ percent.
| A) | 50 to 78.5% |
| B) | 90 to 100% |
| C) | 40.5 to 60% |
| D) | 60 to 80% |
169. An open fuse circuit has a resistance equal to
| A) | Zero |
| B) | Infinity |
| C) | Unity |
| D) | At least 100Ω at standard |
170. Series current negative feedback occurs when the feedback voltage is proportional to the output
| A) | Current |
| B) | Power |
| C) | Voltage |
| D) | Impedance |
171. Which of the following is not a FET amplifier configuration?
| A) | Common source amplifier |
| B) | Common gate amplifier |
| C) | Common drain amplifier |
| D) | Common base amplifier |
172. What capacitors are used in transistor amplifiers?
| A) | Electrolytic |
| B) | Paper |
| C) | Mylar |
| D) | Mica |
173. In an LC circuit, when the capacitor energy is maximum, the inductor energy is
| A) | Zero |
| B) | Half-way between maximum and minimum |
| C) | Maximum |
| D) | Minimum |
174. When the gain versus frequency curve of a transistor amplifier is not flat, distortion is present.
| A) | Frequency |
| B) | Intermodulation |
| C) | Amplitude |
| D) | Phase |
175. Transformer coupling provides high gain because
| A) | Impedance matching can be achieved |
| B) | Transformer is very efficient |
| C) | Transformer steps up the current |
| D) | Transformer steps up the voltage |
176. Which of the following is considered an amplifier figure of merit?
| A) | Gain-bandwidth product |
| B) | Alpha(α) |
| C) | Beta(β) |
| D) | Temperature |
177. If an amplifier has a power gain of 100, then its dB gain is
| A) | 10 |
| B) | 20 |
| C) | 40 |
| D) | 100 |
178. An oscillator produces ______ oscillations.
| A) | Sinusoidal |
| B) | Damped |
| C) | Undamped |
| D) | Modulated |
179. The largest theoretical voltage gain obtained with a common collector amplifier is
| A) | Infinite |
| B) | Unity |
| C) | 10 |
| D) | 100 |
180. Given three amplifiers with a gain of 10 and are connected in cascade. How much is the overall gain?
| A) | 10,000 |
| B) | 20 |
| C) | 24 |
| D) | 30 |
181. In practice, what is normally varied in order to change the frequency of oscillation?
| A) | Resistance |
| B) | Impedance |
| C) | Inductance |
| D) | Capacitance |
182. When a transistor is cut off
| A) | Maximum voltage appears across transistor |
| B) | Maximum current flows |
| C) | Minimum current flows |
| D) | Maximum voltage appears across load |
183. The operating point is generally located at _____ of dc load line in class A operation
| A) | End point |
| B) | Saturation point |
| C) | Cut off point |
| D) | The middle |
184. 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 |
185. To obtain good gain stability in a negative feedback amplifier, AB is
| A) | Zero |
| B) | Equal to 1 |
| C) | Less than 1 |
| D) | Very much greater than 1 |
186. Which of the following amplifier below is a choice when higher power gain is a requirement?
| A) | Hybrid connection |
| B) | Common emitter |
| C) | Common collector |
| D) | Common base |
187. Parasitic oscillations are caused by
| A) | Push-pull operation |
| B) | Poor interstage coupling |
| C) | Output negative feedback |
| D) | Transistor interelectrode capacitance |
188. The impedance of a load must match the impedance of the amplifier so that
| A) | The efficiency can be maintained at low level |
| B) | The signal-to-noise ratio is maximized |
| C) | Maximum power is transferred to the load |
| D) | Minimum power is transferred to the load |
189. Which coupling has the best frequency response?
| A) | Transistor |
| B) | RC |
| C) | Direct |
| D) | Transformer |
190. What is the most important consideration in power amplifiers?
| A) | Amplifier distortion |
| B) | To keep the transformer cool |
| C) | Collector efficiency |
| D) | Biasing the circuit |
191. The push-pull circuit must use _____ operation.
| A) | Class A |
| B) | Class AB |
| C) | Class C |
| D) | Class B |
192. What is the approximate gain of an amplifier with negative feedback?
| A) | The reciprocal of feedback factor plus one |
| B) | The feedback factor plus one |
| C) | The feedback factor |
| D) | The reciprocal of feedback factor |
193. What is the purpose of the bypass capacitor in a common-emitter amplifier?
| A) | It provides ac grounding |
| B) | It decreases voltage gain |
| C) | No effect in the circuit |
| D) | It increases voltage gain |
194. Cascaded amplifiers total decibel gain is equal to
| A) | The difference of the individual gains |
| B) | The sum of the individual gains |
| C) | The quotient of the individual gains |
| D) | The product of the individual gains |
195. What is the typical Q of a crystal?
| A) | More than 10,000 |
| B) | 50 |
| C) | 100 |
| D) | 1000 |
196. A transistor amplifier has high output impedance because
| A) | Collector is wider than emitter or base |
| B) | Emitter is heavily doped |
| C) | Collector has reverse bias |
| D) | Emitter has forward bias |
197. The _____ the voltage regulation, the better the operation of the voltage supply circuit.
| A) | Smaller |
| B) | Moderate |
| C) | Bigger |
| D) | Biggest |
198. The input impedance of an amplifier _____ when negative current feedback is applied.
| A) | Becomes zero |
| B) | Increases |
| C) | Remains unchanged |
| D) | Decreases |
199. The crystal oscillator frequency is very stable due to ____ of the crystal.
| A) | High Q |
| B) | Low Q |
| C) | Rigidity |
| D) | Ductility |
200. The three amplifiers are connected in a multistage arrangement each with a voltage gain of 30.
Compute for the overall voltage gain.
| A) | 30 |
| B) | 27,000 |
| C) | 10 |
| D) | 90 |
201. A type of filter which is having a single continuous transmission band with neither the upper nor the lower cut-off frequencies being zero or infinite is called
| A) | Band pass filter |
| B) | Band stop filter |
| C) | Low pass filter |
| D) | High pass filter |
202. The maximum collector efficiency of class B operation is
| A) | 5% |
| B) | 90% |
| C) | 60.5% |
| D) | 78.5 |
203. An electronic transfer from one stage to the next is termed as
| A) | Mixing |
| B) | Doping |
| C) | Connecting |
| D) | Coupling |
204. What is the piezoelectric effect in a crystal?
| A) | Voltage is developed because of mechanical stress |
| B) | Change of frequency because of temperature |
| C) | Change in resistance because of temperature |
| D) | Current is developed due to force applied |
205. To amplify dc signals, multistage amplifier uses what coupling?
| A) | Resistor |
| B) | Transformer |
| C) | Direct |
| D) | RC |
206. The coupling capacitor Cc must be large enough to ____ in an RC coupling scheme.
| A) | Prevent attenuation of low frequency |
| B) | Pass dc between the stages |
| C) | Dissipate high power |
| D) | Prevent attenuation of high frequency |
207. What represents common-emitter small signal input resistance?
| A) | hoe |
| B) | hfe |
| C) | hib |
| D) | hie |
208. The value of collector load resistance in a transistor amplifier is _____ the output impedance of the transistor.
| A) | Equal to |
| B) | Not related |
| C) | Less than |
| D) | More than |
209. What is the most costly coupling?
| A) | Direct |
| B) | Transformer |
| C) | Inductive |
| D) | RC coupling |
210. The ratio output rms power in watts to the input dc power in watts in the different amplifier class is called .
| A) | Amplification factor |
| B) | Efficiency |
| C) | Gain |
| D) | Phase power |
211. The capacitors are considered _____ in the dc equivalent circuit of a transistor amplifier.
| A) | Partially short |
| B) | Short |
| C) | Partially open |
| D) | Open |
212. Negative feedback is employed in
| A) | Amplifiers |
| B) | Rectifiers |
| C) | Receivers |
| D) | Oscillators |
213. The current in any branch of a transistor amplifier that is operating is
| A) | dc only |
| B) | ac only |
| C) | the difference of ac and dc |
| D) | the sum of ac and dc |
214. What is the device in a transistor oscillator?
| A) | Feedback circuit |
| B) | Biasing circuit |
| C) | Transistor |
| D) | LC tank circuit |
215. When the output of an amplifier is 10V and 100mV from the output is fed back to the input, feedback factor is
| A) | 0.15 |
| B) | 10 |
| C) | 0.1 |
| D) | 0.01 |
216. A dc voltage supply provides 60V when the output is unloaded.
When connected to a load the output drops to 56V.
Calculate the value of the voltage regulation.
| A) | 5% |
| B) | 12% |
| C) | 8.1% |
| D) | 7.1% |
217. One of the items below is a characteristic of cascaded amplifiers?
| A) | Doubles transconductance |
| B) | Increased overall gain |
| C) | Increased overall amplification ratio |
| D) | Total gain is lessen |
218. In an LC oscillator, the frequency of oscillations is given by
| A) | 2π/√LC |
| B) | √LC/2π |
| C) | 4π/√LC |
| D) | 1/(2π√LC) |
219. 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) | 6% |
| D) | 50% |
220. What piece of equipment in an oscilloscope is used to indicate pulse condition in a digital logic circuit?
| A) | Connector |
| B) | Probe |
| C) | Test probe |
| D) | Logic probe |
221. The frequency of oscillation is _____ L and C in an LC oscillator.
| A) | Proportional to square of |
| B) | Inversely proportional to square root of |
| C) | Independent of the values of |
| D) | Directly proportional to |
222. An important limitation of crystal oscillator is
| A) | Less availability of quartz crystal |
| B) | Its high Q |
| C) | Its high output |
| D) | Its low output |
223. Why is it that the size of a power transistor is made considerably large?
| A) | To facilitate connections |
| B) | To simply construction |
| C) | To dissipate more heat |
| D) | To provide easy handling |
224. Why is transformer coupling provides high frequency?
| A) | AC resistance is high |
| B) | DC resistance is low |
| C) | Collector voltage is stepped up |
| D) | Collector voltage is stepped down |
225. What is a non-linear type of amplifier?
| A) | Class A |
| B) | Class AB |
| C) | Class C |
| D) | Class B |
226. An instrument use to measure ones location in terms of coordinates
| A) | ILS |
| B) | FANS |
| C) | GPS |
| D) | GSM |
227. What is usually employed at the output stage of an amplifier?
| A) | Pre-amplifier |
| B) | Class A power amplifier |
| C) | Push-pull amplifier |
| D) | Differential amplifier |
228. An amplifier configuration where the input signal is led to the emitter terminal and the output from the collector terminal is called
| A) | Common base |
| B) | Clipper |
| C) | Common collector |
| D) | Common emitter |
229. CC configuration is used for impedance matching because its
| A) | Output impedance is zero |
| B) | Input impedance is very high |
| C) | Output impedance is very low |
| D) | Input impedance is very low |
230. The output signal of CE amplifier is always
| A) | In phase with the input signal |
| B) | Out of phase with the input signal |
| C) | Equal to the input signal |
| D) | Larger than the input signal |
231. The frequency of the ripple voltage at the output of a full-wave rectifier at 60 cycles.
| A) | 120 cycles |
| B) | 240 cycles |
| C) | 480 cycles |
| D) | 60 cycles |
232. When a FET with a lower transconductance is substituted into a FET amplifier circuit, what happens?
| A) | The circuit disamplifies |
| B) | The current gain does not change |
| C) | The input resistance decreases |
| D) | The voltage gain decreases |
233. In a phase-shift oscillator, ______ RC sections are generally used.
| A) | Five |
| B) | Two |
| C) | Three |
| D) | Four |
234. The current gain of an emitter follower is
| A) | Zero |
| B) | Greater than 1 |
| C) | Equal to 1 |
| D) | Less than 1 |
235. What class of operation is used where a portion of a signal only is required, such as the synchronizing pulse separator of a television receiver?
| A) | Class B |
| B) | Class C |
| C) | Class A |
| D) | Class AB |
236. The approximate operating frequency of a phase shift oscillator is given by
| A) | 1/(2π RC) |
| B) | 1/(29 RC) |
| C) | 1/(2π√LC) |
| D) | 1/(2πRC√6) |
237. A class A power amplifier is otherwise known as
| A) | Differential amplifier |
| B) | Symmetrical amplifier |
| C) | Single ended amplifier |
| D) | Darlington amplifier |
238. The operating point in a transistor amplifier moves along _____ when an ac signal is applied
| A) | both dc and ac load lines |
| B) | cut-off |
| C) | ac load line |
| D) | dc load line |
239. When the collector supply is 5V, then collector cut off voltage under dc condition is
| A) | 5V |
| B) | 2.5V |
| C) | 20V |
| D) | 10V |
240. When a transistor amplifier feeds a load of low resistance, its voltage gain will be
| A) | Low |
| B) | Moderate |
| C) | Very high |
| D) | High |
241. An oscillator converts
| A) | electrical power into mechanical power |
| B) | mechanical power into ac power |
| C) | ac power into dc power |
| D) | dc power into ac power |
242. What is the maximum collector efficiency of a resistance loaded class A power amplifier?
| A) | 78.5% |
| B) | 30% |
| C) | 50% |
| D) | 25% |
243. The power input to a power amplifier is ______ quantity.
| A) | ac |
| B) | sinusoidal |
| C) | Pulsating dc |
| D) | dc |
244. The frequency response of transformer coupling is
| A) | Poor |
| B) | Good |
| C) | Very good |
| D) | Excellent |
245. The basic concept of the electric wave filter was originated by
| A) | Foster |
| B) | Norton |
| C) | Campbell and Wagner |
| D) | Bode and Darlington |
246. Emitter follower is used for
| A) | Current gain |
| B) | Voltage gain |
| C) | Power gain |
| D) | Impedance matching |
247. If Av is 50 Ai is 200, what is the power gain of a common emitter amplifier?
| A) | 100,000 |
| B) | 1,000 |
| C) | 10,000 |
| D) | 100 |
248. The driver stage usually employs _____ amplifier.
| A) | Push-pull |
| B) | Class AB |
| C) | Class C |
| D) | Class A power |
249. Quartz crystal is most commonly used in crystal oscillators because
| A) | It is quite inexpensive |
| B) | It is very rugged |
| C) | It is easily available |
| D) | It has superior electrical properties |
250. The collector current in an common base configuration is equal to
| A) | Alpha times base current plus leakage current |
| B) | Beta times emitter current plus leakage current |
| C) | Beta times collector current plus leakage current |
| D) | Alpha times emitter current plus leakage current |
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