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 4 of the Series
151. In a Colpitt’s oscillator, feedback is obtained
- A. By magnetic induction
- B. By a tickler coil
- C. From the center of split capacitors
- D. From the center of split inductors
152. When the collector resistor in a common emitter amplifier is increased in value the voltage gain
- A. Increases
- B. Decreases
- C. Remain the same
- D. Becomes erratic
153. The output signal of CE amplifier is always
- A. Out of phase with the input signal
- B. Equal to the input signal
- C. In phase with the input signal
- D. Larger than the input signal
154. What is the purpose of capacitors in a transistor amplifier?
- A. To protect the transistor
- B. To cool the transistor
- C. To couple or bypass ac component
- D. To provide biasing
155. What is the phase difference between voltage across collector load and signal voltage in a common emitter amplifier?
- A. 0°
- B. 270°
- C. 180°
- D. 90°
156. When CE configuration is used for an oscillator, the voltage fed back must
- A. Be inverted by 180°
- B. Be taken from a capacitor
- C. Have a 0° phase shift
- D. Taken from an inductor
157. Class B operation has a maximum possible frequency of ______ percent.
- A. 100%
- B. 78.5%
- C. 75%
- D. 2.2%
158. What is the most stable sine-wave oscillator which uses piezo-electric quartz crystal?
- A. Crystal oscillator
- B. Wien-bridge oscillator
- C. DC restorer
- D. Hartley and Colpitts oscillator
159. To sustain oscillations, the power gain of the amplifier may be
- A. Between 0.1 and 0.5
- B. Any value form 0.5 upward
- C. Equal to or greater than 1
- D. Infinite
160. In a phase shift oscillator, 180° phase-shift is obtained
- A. A transformer
- B. LC tank circuit
- C. Three RC sections
- D. Three LC sections
161. Feedback circuit usually employs ________ network
- A. Resistive
- B. Inductive
- C. Capacitive
- D. Active
162. Emitter follower is used for
- A. Impedance matching
- B. Voltage gain
- C. Current gain
- D. Power gain
163. One of the items below is a characteristic of cascaded amplifiers?
- A. Doubles transconductance
- B. Total gain is lessen
- C. Increased overall gain
- D. Increased overall amplification ratio
164. Logic analyzer is used to
- A. Verify the logic operation of the gates in a circuit
- B. To display the fall time
- C. To sample and display systems signal
- D. To analyze the logic operation of the system
165. Quartz crystal is most commonly used in crystal oscillators because
- A. It is easily available
- B. It has superior electrical properties
- C. It is quite inexpensive
- D. It is very rugged
166. The operating frequency of a Wien-bridge oscillator is given by
- A.
- B.
- C.
- D.
167. Which operation gives the maximum distortion?
- A. Class A
- B. Class C
- C. Class B
- D. Class AB
168. Low efficiency of a power amplifier results in
- A. Low forward bias
- B. Less battery consumption
- C. More battery consumption
- D. Low power output
169. In an LC oscillator, the frequency of oscillations is given by
- A.
- B.
- C.
- D.
170. Class A operation has a maximum possible efficiency of ______ percent.
- A. 100%
- B. 50%
- C. 75%
- D. 25%
171. Which of the following amplifier below is a choice when higher power gain is a requirement?
- A. Common base
- B. Common emitter
- C. Common collector
- D. Hybrid connection
172. The signal generator generally used in laboratories is ________ oscillator
- A. Crystal
- B. Wien-bridge
- C. Hartley
- D. Phase-shift
173. A buffer amplifier is used for
- A. Maximum loading and minimum mismatch
- B. Minimum loading and minimum mismatch
- C. Maximum loading and maximum mismatch
- D. Minimum loading and maximum mismatch
174. Parasitic oscillations are caused by
- A. Output negative feedback
- B. Push-pull operation
- C. Poor interstage coupling
- D. Transistor interelectrode capacitance
175. Which is a fixed-frequency oscillator
- A. Phase-shift oscillator
- B. Colpitt’s oscillator
- C. Hartley oscillator
- D. Crystal oscillator
176. The approximate operating frequency of a phase shift oscillator is given by
- A.
- B.
- C.
- D.
177. The frequency of the ripple voltage at the output of a full-wave rectifier at 60 cycles.
- A. 120 cycles
- B. 60 cycles
- C. 240 cycles
- D. 480 cycles
178. Cascaded amplifiers total decibel gain is equal to
- A. The sum of the individual gains
- B. The product of the individual gains
- C. The difference of the individual gains
- D. The quotient of the individual gains
179. In an LC oscillator, if the value of L is increased four times, then the frequency of oscillation is
- A. Decreased 2 times
- B. Decreased 4 times
- C. Increased 2 times
- D. Increased 4 times
180. A class A power amplifier is otherwise known as
- A. Single ended amplifier
- B. Darlington amplifier
- C. Symmetrical amplifier
- D. Differential amplifier
181. The power input to a power amplifier is __________ quantity.
- A. ac
- B. Pulsating dc
- C. dc
- D. sinusoidal
182. When shock-excited, a crystal will produce alternating emf longer than an LC circuit because
- A. has greater mechanical strength
- B. has fewer losses
- C. is small-sized
- D. is very rigid
183. The stability of a regulated power supply is equivalent to
- A. change of output voltage over the change in supply voltage
- B. change in supply voltage over the change of output voltage
- C. product of the output voltage and supply voltage
- D. the difference of an output voltage to its supply voltage
184. What oscillator circuit uses a tapped coil in the tuned circuit?
- A. Hartley
- B. Colpitts
- C. Crystal
- D. Pierce
185. If you move towards an oscillating circuit, its frequency changes because of
- A. Hand capacitance
- B. Movement of the body
- C. Noise of foot
- D. Stray capacitance
186. Which of the following is not a FET amplifier configuration?
- A. Common base amplifier
- B. Common drain amplifier
- C. Common source amplifier
- D. Common gate amplifier
187. The number of transistor in a single stage amplifier is
- A. Two
- B. Three
- C. One
- D. Four
188. Series current negative feedback occurs when the feedback voltage is proportional to the output
- A. Voltage
- B. Impedance
- C. Current
- D. Power
189. Which of the following is NOT an oscillator requirement?
- A. Attenuator
- B. Amplifier
- C. Tank circuit
- D. Feedback
190. An amplifier with efficiency of 85% is likely to be
- A. Class A
- B. Class B
- C. Class AB
- D. Class C
191. What is the phase difference between the output and the input voltage of a CE amplifier?
- A. 180°
- B. 270°
- C. 0°
- D. 90°
192. Class C operation is preferred in oscillators because it
- A. Is more efficient
- B. Gives larger outputs
- C. Produces square waves
- D. Increases stability
193. 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. Sine wave oscillator
- B. Square-wave generator
- C. Relaxation oscillator
- D. Limiter
194. What is the desired input impedance of a transistor?
- A. Low
- B. Very low
- C. High
- D. Very high
195. What is the maximum collector efficiency of class B?
- A. 50%
- B. 90%
- C. 60.5%
- D. 78.5%
196. When a transistor is cut off
- A. Maximum current flows
- B. Maximum voltage appears across load
- C. Maximum voltage appears across transistor
- D. Minimum current flows
197. In an LC circuit, when the capacitor energy is maximum, the inductor energy is
- A. Maximum
- B. Minimum
- C. Half-way between maximum and minimum
- D. Zero
198. What is the approximate gain of an amplifier with negative feedback?
- A. The feedback factor
- B. The reciprocal of feedback factor plus one
- C. The reciprocal of feedback factor
- D. The feedback factor plus one
199. The operating point in a transistor amplifier moves along ________ when an ac signal is applied
- A. dc load line
- B. ac load line
- C. both dc and ac load lines
- D. cut-off
200. An oscillator converts
- A. ac power into dc power
- B. dc power into ac power
- C. mechanical power into ac power
- D. electrical power into mechanical power
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