Previous 100 << Previous 150 << 200
UNIT I - Introduction to Electronics MCQs 151-200
151. is assumed in the clamper.
a. capacitor charges exponentially and discharges instantly.
b. capacitor charges instantly and discharges instantly.
c. capacitor charges instantly and does not discharge at all.
d. capacitor charges exponentially and discharges exponentially.
Ans: c
152. is action used in multiplier.
a. clipping
b. Clamping
c. rectifying
d. slicing
Ans: b
153. In a half wave voltage doubler, the capacitor charges in -------------
a. alternate half cycle
b. each half cycle
c. first positive half cycle
d. none of these
Ans: a
154. The voltage regulation of multipliersis
a. very good
b. poor
c. zero
d. none of these
Ans: b
155. --------- is not required in Voltage multipliers
a. Center tap transformer
b. Diode
c. Capacitor
d. None of these
Ans: a
156. PIV of diode in Full wave doubleris
a. Vm
b. 2Vm
c. 3Vm
d. none
Ans: b
157. The basic circuit of half wave doubleris
a. Clamper
b. Rectifier
c. Clipper
d. Regulator
Ans: a
158. The zener diode is generally operated in
a. Forward breakdown region
b. reverse breakdown region
c. middle breakdown region
d. all above
Ans: b
159. One of the application of zener diode is
a. Clipper
b. Clamper
c. Voltage regulator
d. all above
Ans: c
160.A zener diode.........
a. has a high forward-voltage rating
b. has a sharp breakdown at low reverse voltage
c. is useful as an amplifier
d. has a negative resistance
Ans: b
161.The doping level in a zener diode is ..... that of a semiconductor diode.
a. more than
b. less than
c. the same as
d. none of the above
Ans: a
162.A 12 V zener diode has a 1W power rating. What is the maximum rated zener current?
a. 120 mA
b. 83.3 mA
c. 46.1 mA
d. 1A
Ans: b
163.A general purpose diode is more likely to suffer avalanche breakdown rather than zener breakdown because
a. its leakage current issmall
b. it has weak covalent bonds
c. it is lightly doped
d. it has low reverse resistance
Ans: c
164. Once a zener diode goes into breakdown, its.........doesn’t change much
a. voltage
b. current
c. dynamic impedance
d. capacitance
Ans: a
165. Load regulation is determined by
a. changes in load current and input voltage
b. changes in load current and output voltage
c. changes in load resistance and input voltage
d. changes in zener current and load current
Ans: b
166. For a certain 12 V zener diode, a 10 mA change in zener current produces a 0.1 V change in zener voltage. The Zener impedance for this current range is
a. 1 W
b. 100 W
c. 10 W
d. 0.1 W
Ans: c
167. If the load resistance increases in a zener regulator, the zener current
a. decreases
b. stays the same
c. increases
d. equals the source voltage divided by the series resistance
Ans: c
168. Practically zener diodes are operated in
a. Forward breakdown region
b. reverse breakdown region
c. middle breakdown
d. all above
Ans: b
169.A zener diode has..............
a. one pn-junction
b. two pn-junctions
c. three pn-junctions
d. none of the above
Ans: a
170.A zener diode is operated in the following mode as a voltage stabilizer
a. reverse bias
b. forward bias
c. beyond the breakdown region
d. reverse bias around the knee of breakdown region
Ans: d
171. For a certain 12 V zener diode, a 10 mA change in zener current produces a 0.1 V change in zener voltage. The Zener impedance for this current range is
a. 1 ohm
b. 100 ohm
c. 10 ohm
d. 0.1 ohm
Ans: b
172. An optical diode which emits light when forward biased is
a. LED
b. LCD
c. TFT
d. None of above
Ans: a
173. The color of emitted light decided by
a. Semiconductor material
b. Wavelength
c. type
d. all above
Ans: a
174. The approximate voltage drop across a forward- biased LED is
a. 0.3 V
b. 0.7 V
c. 5.6 V
d. 2.0 V
Ans: d
175. LEDs have replaced incandescent lamps in many applications because they have.......
a. a lower operating voltage
b. a longer life
c. . faster on-off switching
d. all the advantages as a, b,c,d
Ans: d
176. A display using seven LEDs is called
a. bar graph display
b. seven segment display
c. matrix display
d. none of these
Ans: b
177. Which of the following group of letters can be displayed on seven segment display?
a. A,C
b. b,d
c. F,C
d. all of these
Ans: d
178. The internal resistance of a photodiode
a. increases with light intensity when reverse biased
b. decreases with light intensity when reverse biased
c. increases with light intensity when forward biased
d. decreases with light intensity when forward biased
Ans:b
179. To display the digit 0 in a seven segment indicator
a. C must be off
b. G must be off
c. F must be on
d. all segments must be lighted
Ans: b
180. As compared to a silicon rectifier diode, an LED has a
a. lower forward voltage and lower breakdown voltage
b. lower forward voltage and higher breakdown voltage
c. higher forward voltage and lower breakdown voltage
d. higher forward voltage and higher breakdown voltage
Ans: c
181. Types of seven segment display are
a. Common anode type
b. common gate type
c. common cathode type
d. both A and B
Ans: d
182. An infrared LED is optically coupled to a photodiode. When the LED is turned off, the reading on an ammeter in series with the reverse biased photodiode will
a. not change
b. decrease
c. increase
d. fluctuate
Ans: b
183. The semiconductor material used for LEDis
a. Gallium Arsenide
b. gallium bromide
c. Silicon
d. Germanium
Ans: a
184. The graph of response of LED. is called spectral
a. Forward Voltage Vs wavelength
b. Current Vs forward voltage
c. current Vs forward voltage
d. light output Vs wavelength
Ans: d
185. The LED emits light when biased.
a. reverse
b. unbiased
c. forward
d. none of these
Ans: d
186. The LED works on the principle of
a. fluroscence
b. hall effect
c. electroluminescene
d. none of these
Ans: c
187. GaAsP LEDs are used to produce ...... color light.
a. red
b. green
c. orange
d. white
Ans: a
188. The controls the brightness of LED.
a. Forward voltage
b. Forward current
c. Materal used
d. none of these
Ans: b
189. A photodiode operates in condition.
a. reverse biased
b. forward biased
c. parallel with load
d. none of these
Ans: a
190. is always operated in reverse biased condition.
a. LED
b. Photodiode
c. Transistor
d. Rectifier
Ans: b
191. The current in photodiode increases as the light intensity.
a. remains same
b. decreases
c. increases
d. none of these
Ans: c
192. The dark current in photodiode is due to charge carriers.
a. majority
b. minority
c. both the
d. none of these
Ans: b
193. The photodiode is device.
a. photoemitter
b. photorejector
c. photodetector
d. none of these
Ans: d
194. The luminous efficiency of LEDs is .
a. high
b. low
c. zero
d. none of these
Ans: b
195. The luminous measured in .
a. lumens/watt
b. watts/lumen
c. lumens/degree C
d. lumens/ampere
Ans: a
196. is used in optocouplers.
a. Zener quadrant.
b. LED
c. SCR
d. Transformer
Ans: b
197. The photodiode current under no light is called current.
a. forward
b. maximum
c. dark
d. none of these
Ans: c
198. The dark current of photodiode is always
a. large
b. very small
c. zero
d. infinite
Ans: b
199. Photo current is directly proportional to a. forward current
a. first
b. second
c. third
d. fourth
Ans: c
200. The intensity of light is measured in
a. Lm/A
b. Lm/W
c. Lm/w2
d. Lm/m2
Ans: d
201. The photodiode characteristics lies in ..... quadrant.
a. first
b. second
c. third
d. fourth
Ans: c
202. The current is photodiode is due to carriers.
a. majority
b. minority
c. both
d. none of these
Ans: b
203. The LED is device.
a. photoemitter
b. photorejector
c. photodetector
d. none of these
Ans: a
204. A photodiode converts .
a. light energy into chemical energy
b. chemical energy into electrical energy
c. light energy into electrical energy
d. electrical energy into light energy
Ans: c
205. A LED converts .
a. light energy into chemical energy
b. chemical energy into electrical energy
c. light energy into electrical energy
d. electrical energy into light energy
Ans: d
Post a Comment