MCQOPTIONS
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MCQOPTIONS
This section includes 2171 Mcqs, each offering curated multiple-choice questions to sharpen your ENGINEERING SERVICES EXAMINATION (ESE) knowledge and support exam preparation. Choose a topic below to get started.
| 1251. |
The approximate value of input impedance of CE amplifier with emitter resistance RE is given by |
| A. | hie + Ai RE |
| B. | hie + (1 + hfe) RE |
| C. | hie |
| D. | (1 + hfe) RE |
| Answer» D. (1 + hfe) RE | |
| 1252. |
Turn on time of a transistor switch is equal to sum of (where tr is rise time, td is delay time) |
| A. | ts - tr |
| B. | ts - tf |
| C. | td + tr |
| D. | 2tr |
| Answer» D. 2tr | |
| 1253. |
Whenever a JFET operates above pinch-off voltage |
| A. | depletion regions become smaller |
| B. | drain current increase steeply |
| C. | drain current starts decreasing |
| D. | drain current remains nearly constant |
| Answer» E. | |
| 1254. |
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 | |
| 1255. |
When the circuit is switched on, the loop gain of a Wien bridge oscillator is |
| A. | 1 |
| B. | more than 1 |
| C. | less than 1 |
| D. | about 0.5 |
| Answer» C. less than 1 | |
| 1256. |
To protect the diodes in a rectifier and capacitor input filter circuit it is necessary to use |
| A. | surge resistor |
| B. | surge inductor |
| C. | surge capacitor |
| D. | both (a) and (b) |
| Answer» B. surge inductor | |
| 1257. |
In figure, IC ≈ |
| A. | I1 |
| B. | IB |
| C. | 0.5 I1 |
| D. | 0.5 IB |
| Answer» B. IB | |
| 1258. |
In the circuit of figure, the value of re is (neglecting vbe) |
| A. | 100 Ω |
| B. | 75 Ω |
| C. | 50 Ω |
| D. | 25 Ω |
| Answer» E. | |
| 1259. |
Assertion (A): A sine wave with slew rate distortion looks rectangularReason (R): The maximum rate of output voltage change is called slew rate |
| 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» E. | |
| 1260. |
In logarithmic amplifiers, output voltage is equal to |
| A. | K.log₁₀ (input voltage) |
| B. | K.logₑ (input voltage) |
| C. | input voltage |
| D. | 1/input voltage |
| Answer» C. input voltage | |
| 1261. |
In an amplifier the voltage gain is the ratio of |
| A. | output voltage and emitter resistance |
| B. | output voltage and input current |
| C. | output voltage and input voltage |
| D. | none of the above |
| Answer» D. none of the above | |
| 1262. |
A CB amplifier has re = 6 Ω, RL = 600 Ω and a = 0.98. The voltage gain is |
| A. | 100 |
| B. | 600 x 0.98 |
| C. | 98 |
| D. | 6 |
| Answer» D. 6 | |
| 1263. |
In a crystal oscillator of the Colpitt's oscillator type, the crystal is put is place of the |
| A. | resistor R₁ |
| B. | condenser C₂ |
| C. | condenser C₁ |
| D. | inductor L |
| Answer» E. | |
| 1264. |
The circuit shown in figure will act as |
| A. | differentiator |
| B. | adder |
| C. | clipper |
| D. | clamper |
| Answer» D. clamper | |
| 1265. |
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 | |
| 1266. |
The input resistance of JFET ideally approaches |
| A. | zero |
| B. | 1 ohm |
| C. | 100 ohm |
| D. | infinity |
| Answer» E. | |
| 1267. |
In a CE amplifier the ac emitter resistance |
| A. | is zero |
| B. | is high |
| C. | is very high |
| D. | may have any value |
| Answer» B. is high | |
| 1268. |
Self bias is an example of __________ feedback that tends to stabilize the drain current against changes in temperature and JFET replacement. |
| A. | variable |
| B. | low |
| C. | negative |
| D. | positive |
| Answer» D. positive | |
| 1269. |
A push pull amplifier is a |
| A. | power amplifier |
| B. | voltage amplifier |
| C. | current amplifier |
| D. | both power and current amplifier |
| Answer» B. voltage amplifier | |
| 1270. |
At the peak of negative half cycle in figure |
| A. | diode A is forward biased and diode B is reverse biased |
| B. | both diodes are reverse biased |
| C. | both diodes are forward biased |
| D. | diode A is reverse biased and diode B is forward biased |
| Answer» E. | |
| 1271. |
A voltage tripler circuit uses |
| A. | 2 diodes and 2 capacitors |
| B. | 3 diodes and 3 capacitors |
| C. | 2 diodes and 3 capacitors |
| D. | 3 diodes and 2 capacitors |
| Answer» C. 2 diodes and 3 capacitors | |
| 1272. |
Which of the following couplings may cause unwanted clamping? |
| A. | Resistive |
| B. | Inductive |
| C. | Capacitive |
| D. | Both (a) or (b) |
| Answer» D. Both (a) or (b) | |
| 1273. |
The op-amp circuit shown in the figure is a filter. The type of filter and its cut off type of filter and its cut off frequency are respectively. |
| A. | high Pass, 1000 rad/sec |
| B. | low Pass, 100 rad/sec |
| C. | high Pass, 10000 rad/sec |
| D. | low pass, 10000 rad/sec |
| Answer» B. low Pass, 100 rad/sec | |
| 1274. |
Common base configuration is little used because |
| A. | it has low input impedance |
| B. | it has high input impedance |
| C. | it does not heat up |
| D. | it has very high gain |
| Answer» B. it has high input impedance | |
| 1275. |
Which of the following is the point of reference JFET? |
| A. | Drain |
| B. | Gate |
| C. | Source |
| D. | None of the above |
| Answer» D. None of the above | |
| 1276. |
A transistor may fail due to |
| A. | open weld at the wire leads to the semi-conductor |
| B. | short circuit caused by momentary overloads |
| C. | overheating due to circuit failures |
| D. | any of the above |
| Answer» E. | |
| 1277. |
For oscillations to starts, the loop gain A β of the oscillator must be initially |
| A. | less than unity |
| B. | 0.5 |
| C. | 1.0 |
| D. | more than unity |
| Answer» E. | |
| 1278. |
A transistor will operate in inverted region when |
| A. | emitter junction is forward biased and collector junction is reverse biased |
| B. | emitter junction is reverse biased and collector junction is forward biased |
| C. | emitter junction as well as collector junction are forward biased |
| D. | emitter junction as well as collector junction are reverse biased |
| Answer» C. emitter junction as well as collector junction are forward biased | |
| 1279. |
The h parameter equivalent to ac resistance re is |
| A. | hib |
| B. | hfe |
| C. | hob |
| D. | hrb |
| Answer» B. hfe | |
| 1280. |
A full wave rectifier supplies a load of 1 kΩ. The a.c. Voltage applied to the diodes is 220 - 0 - 220 Volts rms. If diode resistance is neglected, then Average d.c. Voltage |
| A. | 220 V |
| B. | 200 V |
| C. | 198 V |
| D. | 0 volts |
| Answer» D. 0 volts | |
| 1281. |
An npn transistor has a Beta cutoff frequency fβ of 1 MHz, and a common emitter short circuit low frequency current gain β0 of 200. It unity gain frequency fT and the alpha cut off frequency fa2 respectively are |
| A. | 200 MHz, 201 MHz |
| B. | 200 MHz, 199 MHz |
| C. | 199 MHz, 200 MHz |
| D. | 201 MHz, 200 MHz |
| Answer» B. 200 MHz, 199 MHz | |
| 1282. |
In a FET, gm varies as |
| A. | IDS |
| B. | IDS2 |
| C. | 1/IDS |
| D. | √IDS |
| Answer» E. | |
| 1283. |
A Hartley oscillator is used for |
| A. | very low frequencies |
| B. | radio frequencies |
| C. | micro wave frequencies |
| D. | audio frequency |
| Answer» C. micro wave frequencies | |
| 1284. |
Which of the following represents the equivalent circuit of a crystal for crystal oscillator? |
| A. | Figure A |
| B. | Figure B |
| C. | Figure C |
| D. | None of the above |
| Answer» D. None of the above | |
| 1285. |
The coupling capacitor mainly affects |
| A. | bandwidth |
| B. | lower cut-off frequency |
| C. | higher cut-off frequency |
| D. | both lower as well as higher cut-off frequency |
| Answer» C. higher cut-off frequency | |
| 1286. |
For an amplifier the power gain in decibels will be equal to voltage gain in decibels only when |
| A. | R0 = 0 |
| B. | R0 = Ri = 90 |
| C. | R0 = Ri |
| D. | Ri = 0 |
| Answer» D. Ri = 0 | |
| 1287. |
The purpose of using negative feedback in a op-amps is to |
| A. | stabilize overall gain |
| B. | increase output |
| C. | stabilize overall gain and increase output |
| D. | increase output and decrease input |
| Answer» B. increase output | |
| 1288. |
A bridge rectifier circuit has a dc load current of 10 mA and a filter capacitance of 1000 μF. The peak to peak ripple voltage is |
| A. | 0.01 V |
| B. | 0.05 V |
| C. | 0.1 V |
| D. | 0.5 V |
| Answer» D. 0.5 V | |
| 1289. |
Rise time in a transistor is change from |
| A. | 10% of its final value to 90% of its final value |
| B. | 0% of its final value to 90% of its final value |
| C. | 10% of its final value to 100% of its final value |
| D. | 10% to its final value to 50% of its final value |
| Answer» B. 0% of its final value to 90% of its final value | |
| 1290. |
Assertion (A): A common collector amplifier is used for matching a high impedance source to a low impedance loadReason (R): A common collector amplifier has a near unity voltage gain |
| 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 | |
| 1291. |
An engineer designs an amplifier to have a voltage gain of 60, but when constructed it only had a gain of 50. What value of feedback will double the gain? |
| A. | +0.5% |
| B. | +0.66% |
| C. | +1% |
| D. | +3.3% |
| Answer» D. +3.3% | |
| 1292. |
In a voltage regulated power supply the zener operates in the breakdown region when (Vin is input voltage and Vz is zener breakdown voltage) |
| A. | Vin < Vz |
| B. | Vin > Vz |
| C. | Vin = Vz |
| D. | both (a) or (b) |
| Answer» C. Vin = Vz | |
| 1293. |
The current through common emitter resistor of a differential amplifier is called |
| A. | differential current |
| B. | emitter current |
| C. | ground current |
| D. | tail current |
| Answer» E. | |
| 1294. |
In figure VCEQ for each transistor is |
| A. | VCC |
| B. | 0.5 VCC |
| C. | 0.75 VCC |
| D. | 0.25 VCC |
| Answer» C. 0.75 VCC | |
| 1295. |
In figure the voltage drop across diode is 0.7 V. Then the voltage across diode during negative half cycle is |
| A. | 10 V |
| B. | 9.3 V |
| C. | zero |
| D. | 10.7 V |
| Answer» B. 9.3 V | |
| 1296. |
The purpose of providing groundings rings with MOSFET is to |
| A. | avoid any stray voltage at the gate that may destroy SiO₂ layer |
| B. | protect against any descaling |
| C. | ground all eddy currents |
| D. | protect against any physical injury |
| Answer» B. protect against any descaling | |
| 1297. |
Drain feedback bias is often used with |
| A. | D MOSFETs |
| B. | E MOSFETs |
| C. | both D and E MOSFETs |
| D. | neither D nor E MOSFETs |
| Answer» C. both D and E MOSFETs | |
| 1298. |
Assertion (A): Direct coupled amplifiers are rarely usedReason (R): Direct coupled amplifiers suffer from the disadvantage of drift |
| 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 | |
| 1299. |
The common emitter short circuit current gain β of a transistor |
| A. | is a monotonically increasing function of the collector current Ic |
| B. | is a monotonically decreasing function of Ic |
| C. | increasing with Ic, for low Ic, reaches a maximum and then decreases with further increase in Ic |
| D. | is not a function of Ic |
| Answer» D. is not a function of Ic | |
| 1300. |
In figure the current through resistor R |
| A. | is always equal to 130 mA |
| B. | may vary between 130 mA and 10 mA |
| C. | may vary between 65 mA and 10 mA |
| D. | is always equal to 65 mA |
| Answer» B. may vary between 130 mA and 10 mA | |