This is the Multiples Choice Questions Part 3 of the Series in Electronic (Audio/RF) Circuit/Analysis/Design as one of the Electronics Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Electronics Engineering field, Electronics Books, Journals and other Electronics References.
MCQ Topic Outline included in ECE Board Exam Syllabi
- MCQ in Oscillators
- MCQs in Rectifier
- MCQs in Filters
- MCQs in Voltage Regulation
Continue Practice Exam Test Questions Part 3 of the Series
Choose the letter of the best answer in each questions.
101. The three amplifiers are connected in a multistage arrangement each with a voltage gain of 30. Compute for the overall voltage gain.
A. 90
B. 27,000
C. 10
D. 30
Answer: Option A
Solution:
102. If Av is 50 Ai is 200, what is the power gain of a common emitter amplifier?
A. 1,000
B. 10,000
C. 100
D. 100,000
Answer: Option B
Solution:
103. The gain of an amplifier with feedback is known as __________ gain.
A. Closed loop
B. Resonant
C. Open loop
D. Unity
Answer: Option A
Solution:
104. Negative feedback is employed in
A. Oscillators
B. Rectifiers
C. Amplifiers
D. Receivers
Answer: Option C
Solution:
105. The gain of an amplifier is expressed in dB unit because
A. It is a simple unit
B. Calculations become easy
C. Human ear response is logarithmic
D. It is the most appropriate unit
Answer: Option C
Solution:
106. What is the typical value of the emitter bypass capacitor CE in a multistage amplifier?
A. About 0.1 µF
B. About 50 µF
C. About 100 pF
D. About 0.01 µF
Answer: Option B
Solution:
107. In a multistage amplifier, if the stages have R and C component only, ___________ operation is apparent.
A. Class B
B. Class C
C. Class A
D. Class AB
Answer: Option C
Solution:
108. In practice, what is normally varied in order to change the frequency of oscillation?
A. Capacitance
B. Inductance
C. Resistance
D. Impedance
Answer: Option A
Solution:
109. What is the main consideration in the output stage of an amplifier?
A. Power output
B. Voltage gain
C. Power gain
D. Current gain
Answer: Option C
Solution:
110. Transformer coupling provides high gain because
A. Transformer is very efficient
B. Impedance matching can be achieved
C. Transformer steps up the voltage
D. Transformer steps up the current
Answer: Option B
Solution:
111. When negative voltage feedback is applied to an amplifier, its output impedance
A. Remains unchanged
B. Decreases
C. Increases
D. Becomes zero
Answer: Option B
Solution:
112. An LC oscillator cannot be used to produce ____________ frequencies.
A. High
B. Very high
C. Audio
D. Very low
Answer: Option D
Solution:
113. A transistor converts
A. Dc power into ac power
B. Ac power into dc power
C. High resistance into low resistance
D. Low resistance into high resistance
Answer: Option A
Solution:
114. Hartley oscillator is commonly used in which of the following?
A. Radio receivers
B. TV receivers
C. Radio transmitters
D. CATV
Answer: Option A
Solution:
115. An oscillator oscillates due to
A. Negative feedback
B. Positive feedback
C. Both positive and negative feedback
D. Neither positive nor negative feedback
Answer: Option B
Solution:
116. Generally tuned amplifiers are operated in
A. Class C
B. Class A
C. Class B
D. Class AB
Answer: Option A
Solution:
117. A tuned amplifier is used in what application?
A. Radio frequency
B. Audio frequency
C. Intermediate frequency
D. Low frequency
Answer: Option A
Solution:
118. What is the ratio of output to input impedance of a CE amplifier?
A. Very low
B. Very high
C. Moderate
D. Approximately 1
Answer: Option C
Solution:
119. For a constant output frequency, the simplest sinusoidal oscillator is the ___________.
A. Crystal oscillator
B. Phase-shift circuit
C. Colpitts circuits
D. Hartley circuit
Answer: Option A
Solution:
120. The frequency stability of the oscillator output is maximum in ____________ oscillator.
A. LC
B. Crystal
C. Phase-shift
D. Wien bridge
Answer: Option D
Solution:
121. Transformer coupling introduces what type of distortion?
A. Amplitude
B. Frequency
C. Phase
D. Intermodulation
Answer: Option B
Solution:
122. A pulsating dc applied to power amplifiers causes
A. Burning of transistor
B. Hum in the circuit
C. Excessive forward voltage
D. Excessive reverse voltage
Answer: Option B
Solution:
123. What is the disadvantage of impedance matching?
A. It gives distorted output
B. It requires a transformer
C. It gives low power output
D. It is expensive
Answer: Option A
Solution:
124. In a phase-shift oscillator, ____________ RC sections are generally used.
A. Three
B. Four
C. Two
D. Five
Answer: Option A
Solution:
125. In phase-shift oscillator, what are the frequency determining elements?
A. L and C
B. R, L and C
C. R and C
D. R and L
Answer: Option C
Solution:
126. When the gain is 20 without feedback and 12 with negative feedback, feedback factor is
A. 0.033
B. 3/5
C. 5/3
D. 1/5
Answer: Option A
Solution:
127. The input impedance of which amplifier depends strongly on load resistance?
A. CE
B. CC
C. CB
D. CD
Answer: Option B
Solution:
128. What capacitors are used in transistor amplifiers?
A. Paper
B. Electrolytic
C. Mica
D. Mylar
Answer: Option B
Solution:
129. An important limitation of crystal oscillator is
A. Its low output
B. Its high Q
C. Less availability of quartz crystal
D. Its high output
Answer: Option A
Solution:
130. What type of feedback is used in Wien bridge oscillator?
A. Positive
B. Negative
C. Both positive and negative
D. Either positive or negative
Answer: Option C
Solution:
131. 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. 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
D. The output resistance is equal to the output resistance of the first stage unless feedback is applied.
Answer: Option D
Solution:
132. What is the most costly coupling?
A. RC coupling
B. Direct
C. Transformer
D. Inductive
Answer: Option C
Solution:
133. When the output of an amplifier is 10V and 100mV from the output is fed back to the input, feedback factor is
A. 10
B. 0.1
C. 0.01
D. 0.15
Answer: Option C
Solution:
134. What is the piezoelectric effect in a crystal?
A. Voltage is developed because of mechanical stress
B. Change in resistance because of temperature
C. Change of frequency because of temperature
D. Current is developed due to force applied
Answer: Option A
Solution:
135. The input resistance of a common emitter amplifier is affected by
A. Re, re and β
B. Rc and re
C. β and re
D. α and re
Answer: Option A
Solution:
136. What is the typical Q of a crystal?
A. 100
B. 50
C. 1000
D. More than 10,000
Answer: Option D
Solution:
137. What is the axis that connects the corners of a crystal?
A. X
B. Mechanical
C. Y
D. Z
Answer: Option A
Solution:
138. Determine the attenuation in dB for a T-pad for which R1=R2=40Ω and R3= 36 Ω. The pad connects a 50 Ω generator to a 50 Ω load.
A. 9.83 dB
B. 83.93 dB
C. 10.83 dB
D. 11.93 dB
Answer: Option A
Solution:
139. What is usually employed at the output stage of an amplifier?
A. Class A power amplifier
B. Push-pull amplifier
C. Pre-amplifier
D. Differential amplifier
Answer: Option B
Solution:
140. Why is it that the size of a power transistor is made considerably large?
A. To provide easy handling
B. To dissipate more heat
C. To simply construction
D. To facilitate connections
Answer: Option B
Solution:
141. When crystal frequency increases with temperature, it has ______________ temperature co- efficient.
A. Positive
B. Negative
C. Zero
D. Infinite
Answer: Option A
Solution:
142. What is the purpose of the bypass capacitor in a common-emitter amplifier?
A. It increases voltage gain
B. It decreases voltage gain
C. It provides ac grounding
D. No effect in the circuit
Answer: Option A
Solution:
143. An emitter follower is equivalent to
A. Common emitter amplifier
B. Common collector amplifier
C. Common base amplifier
D. Hybrid connection
Answer: Option B
Solution:
144. The crystal oscillator frequency is very stable due to ___________ of the crystal.
A. Rigidity
B. Ductility
C. High Q
D. Low Q
Answer: Option C
Solution:
145. The bandwidth of an amplifier _____________ when negative feedback is applied.
A. Decreases
B. Remains unchanged
C. Becomes infinite
D. Increases
Answer: Option D
Solution:
146. The term 1+ A β in the expression for gain with negative feedback is known as
A. Gain factor
B. Sacrifice factor
C. Feedback factor
D. Quality factor
Answer: Option B
Solution:
147. Emitter follower employs ____________ negative feedback.
A. 50%
B. 25%
C. 75%
D. 100%
Answer: Option D
Solution:
148. What application where one would most likely find a crystal oscillator?
A. Radio transmitter
B. AF generator
C. Radio receiver
D. Oscilloscope
Answer: Option A
Solution:
149. What is the most important consideration in power amplifiers?
A. Collector efficiency
B. Biasing the circuit
C. To keep the transformer cool
D. Amplifier distortion
Answer: Option A
Solution:
150. When the gain versus frequency curve of a transistor amplifier is not flat, __________ distortion is present.
A. Amplitude
B. Frequency
C. Intermodulation
D. Phase
Answer: Option B
Solution:
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Questions and Answers in Electronic Circuits
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