Multiple Choice Questions Topic Outline
- MCQs in Amplifiers
- MCQs in Oscillators
- MCQs in Rectifier
- MCQs in Filters
- MCQs in Voltage Regulation
The Series
Following is the list of multiple choice questions in this brand new series:
Continue Practice Exam Test Questions Part 3 of the Series
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
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
103. The gain of an amplifier with feedback is known as _______ gain.
- A. Closed loop
- B. Resonant
- C. Open loop
- D. Unity
104. Negative feedback is employed in
- A. Oscillators
- B. Rectifiers
- C. Amplifiers
- D. Receivers
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
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
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
108. In practice, what is normally varied in order to change the frequency of oscillation?
- A. Capacitance
- B. Inductance
- C. Resistance
- D. Impedance
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
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
111. When negative voltage feedback is applied to an amplifier, its output impedance
- A. Remains unchanged
- B. Decreases
- C. Increases
- D. Becomes zero
112. An LC oscillator cannot be used to produce ______ frequencies.
- A. High
- B. Very high
- C. Audio
- D. Very low
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
114. Hartley oscillator is commonly used in which of the following?
- A. Radio receivers
- B. TV receivers
- C. Radio transmitters
- D. CATV
115. An oscillator oscillates due to
- A. Negative feedback
- B. Positive feedback
- C. Both positive and negative feedback
- D. Neither positive nor negative feedback
116. Generally tuned amplifiers are operated in
- A. Class C
- B. Class A
- C. Class B
- D. Class AB
117. A tuned amplifier is used in what application?
- A. Radio frequency
- B. Audio frequency
- C. Intermediate frequency
- D. Low frequency
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
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
120. The frequency stability of the oscillator output is maximum in _________ oscillator.
- A. LC
- B. Crystal
- C. Phase-shift
- D. Wien bridge
121. Transformer coupling introduces what type of distortion?
- A. Amplitude
- B. Frequency
- C. Phase
- D. Intermodulation
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
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
124. In a phase-shift oscillator, _________ RC sections are generally used.
- A. Three
- B. Four
- C. Two
- D. Five
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
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
127. The input impedance of which amplifier depends strongly on load resistance?
- A. CE
- B. CC
- C. CB
- D. CD
128. What capacitors are used in transistor amplifiers?
- A. Paper
- B. Electrolytic
- C. Mica
- D. Mylar
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
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
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.
132. What is the most costly coupling?
- A. RC coupling
- B. Direct
- C. Transformer
- D. Inductive
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
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
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
136. What is the typical Q of a crystal?
- A. 100
- B. 50
- C. 1000
- D. More than 10,000
137. What is the axis that connects the corners of a crystal?
- A. X
- B. Mechanical
- C. Y
- D. Z
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
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
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
141. When crystal frequency increases with temperature, it has ________ temperature co- efficient.
- A. Positive
- B. Negative
- C. Zero
- D. Infinite
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
143. An emitter follower is equivalent to
- A. Common emitter amplifier
- B. Common collector amplifier
- C. Common base amplifier
- D. Hybrid connection
144. The crystal oscillator frequency is very stable due to __________ of the crystal.
- A. Rigidity
- B. Ductility
- C. High Q
- D. Low Q
145. The bandwidth of an amplifier ________ when negative feedback is applied.
- A. Decreases
- B. Remains unchanged
- C. Becomes infinite
- D. Increases
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
147. Emitter follower employs ________ negative feedback.
- A. 50%
- B. 25%
- C. 75%
- D. 100%
148. What application where one would most likely find a crystal oscillator?
- A. Radio transmitter
- B. AF generator
- C. Radio receiver
- D. Oscilloscope
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
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
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