MCQOPTIONS
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MCQOPTIONS
This section includes 1136 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 351. |
In an RC-coupled amplifier for improving the low frequency response |
| A. | less gain is provided |
| B. | higher CC is used |
| C. | Precision integrator |
| D. | Hartley oscillator |
| Answer» E. | |
| 352. |
A semi-conductor device that behaves like two SCRs is |
| A. | JFET |
| B. | TRIAC |
| C. | has low input impedance |
| D. | has high input impedance |
| Answer» E. | |
| 353. |
The collector voltage VC of the circuit shown in the given figure aside is approximately |
| A. | 2 V |
| B. | 4.6 V |
| C. | 8 V |
| D. | 8.6 V |
| Answer» C. 8 V | |
| 354. |
In figure the coordinates of Q point on the load line are (Neglect VBE) |
| A. | IC = 10 mA, VCE = 15 V |
| B. | IC = 5 mA, VCE = 22.5 V |
| C. | IC = 5 mA, VCE = 15 V |
| D. | IC = 10 mA, VCE = 22.5 V |
| Answer» B. IC = 5 mA, VCE = 22.5 V | |
| 355. |
An RC oscillator uses |
| A. | at least three RC combinations |
| B. | either (a) or (b) |
| C. | high gain |
| D. | high output impedance |
| Answer» D. high output impedance | |
| 356. |
Assertion (A): In CC amplifier the collector is at ac ground Reason (R): CC amplifier is also called emitter follower |
| A. | Both A and R are correct and R is correct explanation for A |
| B. | Both A and R are correct but R is not correct explanation for A |
| C. | A is correct R is wrong |
| D. | A is wrong R is correct |
| Answer» B. Both A and R are correct but R is not correct explanation for A | |
| 357. |
The current ICBO flows in |
| A. | base and emitter leads |
| B. | base and collector leads |
| C. | collector and emitter leads |
| D. | collector, emitter and base leads |
| Answer» C. collector and emitter leads | |
| 358. |
If the output current wave shape of class C circuit has a period of 1 μs and a pulse width of 0.006 μs, the duty cycle is |
| A. | 0.06 |
| B. | 0.006 |
| C. | 0.0001 |
| D. | 0.0006 |
| Answer» C. 0.0001 | |
| 359. |
The thermal resistance of a BJT is about |
| A. | 100° C/W |
| B. | 200° C/W |
| C. | 20° C/W |
| D. | 2° C/W |
| Answer» C. 20¬∞ C/W | |
| 360. |
In figure VCEQ for each transistor is |
| A. | 0.75 VCC |
| B. | 0.25 VCC |
| C. | Two CE stages |
| D. | CE and CC stages |
| Answer» C. Two CE stages | |
| 361. |
In an amplifier, if the output current flows for 120° of the input cycle, the class of amplifier will be |
| A. | A |
| B. | B |
| C. | C |
| D. | AB |
| Answer» D. AB | |
| 362. |
Assertion (A): In a full wave rectifier output the lowest ac component is at twice the input frequencyReason (R): In a full wave rectifier, the output waveform consists of half sinusoids |
| A. | Both A and R are correct and R is correct explanation for A |
| B. | Both A and R are correct but R is not correct explanation for A |
| C. | A is correct R is wrong |
| D. | A is wrong R is correct |
| Answer» C. A is correct R is wrong | |
| 363. |
Typical values of current gains for CE, CB and CC amplifiers are |
| A. | 120, 120 and 1 respectively |
| B. | 120, 1 and 120 respectively |
| C. | 1, 120 and 120 respectively |
| D. | 1, 1 and 120 respectively |
| Answer» C. 1, 120 and 120 respectively | |
| 364. |
If f is more than funity the gain of op-amp becomes less than 1. |
| A. | 1 |
| B. | |
| C. | A |
| D. | AB |
| Answer» B. | |
| 365. |
A second order active bandpass filter can be obtained by cascading LP second order filter having higher cut off frequency fOH with a second order HP filter having lower cut off frequency fOL provided |
| A. | fOL < fOH |
| B. | fOL > fOH |
| C. | fOH = fOL |
| D. | fOH < 0.5 fOL |
| Answer» B. fOL > fOH | |
| 366. |
In figure the trace on the CRO will be |
| A. | half rectifier wave |
| B. | clamped wave |
| C. | no trace at all |
| D. | either (a) or (b) |
| Answer» D. either (a) or (b) | |
| 367. |
Barkhausen criterion is 1 + Avβ = 0. |
| A. | 1 |
| B. | |
| C. | CB |
| D. | CE |
| Answer» B. | |
| 368. |
In order to obtain triangular pulses at the output of the circuit in the figure, the input should be. |
| A. | grounded |
| B. | a square wave |
| C. | Triangular wave |
| D. | Trigger |
| Answer» B. a square wave | |
| 369. |
IF VCC = 15 V, VCEQ = 5 V and ICQ = 50 mA, the efficiency in class A operation is |
| A. | 1 |
| B. | 0.5 |
| C. | 0.25 |
| D. | 0.167 |
| Answer» E. | |
| 370. |
In a CE amplifier the ac signal is increased. Which of the following will not change? |
| A. | Ac base voltage |
| B. | Ac collector voltage |
| C. | Ac emitter voltage |
| D. | Ac collector voltage and ac emitter voltage |
| Answer» D. Ac collector voltage and ac emitter voltage | |
| 371. |
For a BJT if β = 50, ICEO = 3 μA and IC = 1.2 mA then IB |
| A. | 20 μA |
| B. | 10 μA |
| C. | 20 V |
| D. | 10 V |
| Answer» B. 10 ŒºA | |
| 372. |
A Wien bridge oscillator uses |
| A. | negative feedback |
| B. | positive feedback |
| C. | both negative and positive feedback |
| D. | none of the above |
| Answer» D. none of the above | |
| 373. |
Primary advantage of a crystal oscillator is that |
| A. | it can oscillate at any frequency |
| B. | it gives a high O/P voltage |
| C. | its frequency of oscillation remains almost constant |
| D. | it operates on a very low dc supply voltage |
| Answer» D. it operates on a very low dc supply voltage | |
| 374. |
In a CE amplifier circuit the emitter by pass capacitor is remove. The ac output voltage |
| A. | increases |
| B. | remains the same |
| C. | increases or decreases |
| D. | decreases |
| Answer» E. | |
| 375. |
In a half wave voltage doubler circuit the input frequency is 50 Hz. The ripple frequency is |
| A. | 25 Hz |
| B. | 50 Hz |
| C. | 100 Hz |
| D. | 150 Hz |
| Answer» C. 100 Hz | |
| 376. |
A clipper |
| A. | adds a dc component to the input signal |
| B. | removes signal voltages above or below a specified value |
| C. | both (a) and (b) |
| D. | either (a) or (b) |
| Answer» C. both (a) and (b) | |
| 377. |
In a transistor the minimum and maximum values of βdc are 100 and 121. The proper value of βdc to be used to locate Q point is |
| A. | 100 |
| B. | 121 |
| C. | 110.5 |
| D. | 110 |
| Answer» E. | |
| 378. |
Assertion (A): In a circuit using FET, gate is approximately at dc groundReason (R): Self bias stabilizes the quiescent operating point against changes in JFET parameters |
| A. | A is correct R is wrong |
| B. | A is wrong R is correct |
| C. | CE and CC |
| D. | both CE |
| Answer» C. CE and CC | |
| 379. |
In a cascade amplifier, the intermediate stages are always in |
| A. | CC configuration |
| B. | CB configuration |
| C. | CE configuration |
| D. | any of the above |
| Answer» D. any of the above | |
| 380. |
An ideal power supply has |
| A. | zero internal resistance |
| B. | very high internal resistance |
| C. | high output resistance |
| D. | both (b) and (c) |
| Answer» B. very high internal resistance | |
| 381. |
Assume that op-amp in figure is ideal. If input Vi is triangular, the output V0 will be |
| A. | square wave |
| B. | sine wave |
| C. | triangular wave |
| D. | parabolic wave |
| Answer» B. sine wave | |
| 382. |
Assertion (A): Transformer coupling has the disadvantage of the weight of transformer and Saturation of coreReason (R): Transformer coupling is very suitable for impedance matching |
| A. | Both A and R are correct and R is correct explanation for A |
| B. | Both A and R are correct but R is not correct explanation for A |
| C. | A is correct R is wrong |
| D. | A is wrong R is correct |
| Answer» C. A is correct R is wrong | |
| 383. |
In the circuit of figure the diode |
| A. | will conduct as the whole cycle |
| B. | will conduct in the positive half cycle |
| C. | will not conduct |
| D. | will conduct from 30° to 150° in the positive half cycle |
| Answer» D. will conduct from 30¬∞ to 150¬∞ in the positive half cycle | |
| 384. |
In the circuit shown in the figure |
| A. | only red will glow |
| B. | only green will glow |
| C. | both red and green will glow |
| D. | none will glow |
| Answer» B. only green will glow | |
| 385. |
Lower chip area requirements of MOS is advantage in |
| A. | low power circuits |
| B. | high power circuits |
| C. | repetitive operation circuits |
| D. | large scale integration |
| Answer» E. | |
| 386. |
In a N-P-N transistor of the emitter junction is reverse biased and collector junction is also reversed biased, the transistor will operate in |
| A. | cut-off region |
| B. | inverted region |
| C. | video amplifier of a TV receiver |
| D. | IF amplifier of an FM receiver |
| Answer» D. IF amplifier of an FM receiver | |
| 387. |
In figure the zener has a resistance of 5 ohms. As the load resistance is varied, the output voltage |
| A. | will remain constant at 12 V |
| B. | will vary between 12.05 and 12.65 V |
| C. | will vary from 10 to 20 V |
| D. | will remain constant at 12.05 V |
| Answer» C. will vary from 10 to 20 V | |
| 388. |
The advantage of using crystal oscillator is that it |
| A. | requires low d.c. supply voltage |
| B. | works at high frequency |
| C. | gives high output voltage |
| D. | gives constant frequency of oscillations |
| Answer» E. | |
| 389. |
In a transistor CE mode, VCC = +30 V. If the transistor is in cut off region, VCE = |
| A. | +30 V |
| B. | +20 V |
| C. | 10 V |
| D. | zero |
| Answer» B. +20 V | |
| 390. |
In CC configuration, the output signals has approximately |
| A. | the same amplitude and phase |
| B. | opposite amplitude and phase |
| C. | same amplitude but opposite phase |
| D. | none of the above |
| Answer» B. opposite amplitude and phase | |
| 391. |
A JFET can operate on |
| A. | enhancement mode only |
| B. | depletion mode only |
| C. | both depletion as well as enhancement modes |
| D. | neither depletion nor enhancement mode |
| Answer» C. both depletion as well as enhancement modes | |
| 392. |
If it is desired to have low output impedance in an amplifier circuit then we should use |
| A. | common collector circuit |
| B. | common base circuit |
| C. | common emitter circuit |
| D. | either (b) or (c) |
| Answer» B. common base circuit | |
| 393. |
Assertion (A): Linear ICs include audio amplifier, wideband amplifier, RF amplifier and IF amplifierReason (R): The error voltage in a feedback circuit is very small |
| A. | Both A and R are correct and R is correct explanation for A |
| B. | Both A and R are correct but R is not correct explanation for A |
| C. | A is correct R is wrong |
| D. | A is wrong R is correct |
| Answer» C. A is correct R is wrong | |
| 394. |
A quiescent state of a transistor implies |
| A. | zero bias |
| B. | no output |
| C. | no distortion |
| D. | no input signal |
| Answer» D. no input signal | |
| 395. |
The Vo of the op-amp circuit shown in the given is |
| A. | 11 Vi |
| B. | 10 Vi |
| C. | Vi |
| D. | zero |
| Answer» E. | |
| 396. |
Which of the following values represents the open loop gain of typical op-amp? |
| A. | 100 |
| B. | 10000 |
| C. | 100000 |
| D. | 1000000 |
| Answer» D. 1000000 | |
| 397. |
MOS circuits as compared to bipolar circuits take |
| A. | more chip area |
| B. | less chip area |
| C. | same chip area |
| D. | none of these |
| Answer» C. same chip area | |
| 398. |
For full wave rectification four diode bridge rectifier is claimed to have following advantages: Less expensive transformerSmall size transformerSuitable for higher voltage applications Which of these are correct? |
| A. | 1 and 2 only |
| B. | 1 and 3 only |
| C. | 2 and 2 only |
| D. | 1, 2, 3 |
| Answer» E. | |
| 399. |
The name field effect is related to the __________ layers of a JFET. |
| A. | depletion |
| B. | drain |
| C. | source |
| D. | gate |
| Answer» B. drain | |
| 400. |
In figure, secondary winding has 40 turns. For maximum power transformer to 2 ohm resistance the number of turns in primary is |
| A. | 20 |
| B. | 40 |
| C. | 80 |
| D. | 160 |
| Answer» D. 160 | |