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.
| 1051. |
In a self bias circuit for CE amplifier, the base voltage is |
| A. | equal to supply voltage |
| B. | more than supply voltage |
| C. | equal to or more than supply voltage |
| D. | less than supply voltage |
| Answer» E. | |
| 1052. |
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 | |
| 1053. |
Assertion (A): In the circuit shown figure the diode is used to protect the active devices. Transistor T goes into saturation when a positive pulse is applied at base and non conductingReason (R): When the current in an inductor is suddenly stopped, a high voltage is induced across it. |
| 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 | |
| 1054. |
IF VCC = 15 V, VCEQ = 5 V and ICQ = 50 mA, the efficiency in class A operation is |
| A. | 100% |
| B. | 50% |
| C. | 25% |
| D. | 16.7% |
| Answer» E. | |
| 1055. |
In oscillator circuits the energy feedback to its input terminal from output is |
| A. | always in phase with the input signal |
| B. | 90° out of phase with the input signal |
| C. | 180° out of phase with the input signal |
| D. | 270° out of phase with the input signal |
| Answer» D. 270° out of phase with the input signal | |
| 1056. |
The circuit consisting of two transistor connected in series with the d.c. supply voltage is called |
| A. | push pull |
| B. | differential pair |
| C. | stacked V⁺ |
| D. | complementary symmetry |
| Answer» D. complementary symmetry | |
| 1057. |
In a self bias circuit for CE amplifier, the emitter resistance is made three times the original value. The collector current will |
| A. | remain the same |
| B. | become three times |
| C. | decrease |
| D. | become one-third |
| Answer» E. | |
| 1058. |
A full wave rectifier circuit using centre tapped transformer, the input frequency 50 Hz. The frequency of output is |
| A. | 100 Hz |
| B. | 50 Hz |
| C. | 25 Hz |
| D. | none of the above |
| Answer» B. 50 Hz | |
| 1059. |
In the circuit of figure diode will conduct |
| A. | from 90 to 180° in the positive half cycle |
| B. | from 30° to 180° in the positive half cycle |
| C. | from 50° to 160° in the positive half cycle |
| D. | from 30° to 150° in the positive half cycle |
| Answer» E. | |
| 1060. |
Negative feedback lowers the cut off frequency and increase the upper cut off frequency of amplifier. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 1061. |
The gain of a source follower is unity. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 1062. |
Assertion (A): The main use of positive feedback is in oscillator circuits.Reason (R): In an oscillator the loop gain Aβ is kept slightly more than unity |
| 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 | |
| 1063. |
A multivibrator generates |
| A. | sinusoidal waveforms |
| B. | non-sinusoidal waveforms |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» B. non-sinusoidal waveforms | |
| 1064. |
The equivalent circuit shown in figure is for |
| A. | CE |
| B. | CB |
| C. | CC |
| D. | None of the above |
| Answer» D. None of the above | |
| 1065. |
If the midband gain of an amplifier is 40 dB, the gain at half power frequency is |
| A. | 37 dB |
| B. | 30 dB |
| C. | 20 dB |
| D. | 13 dB |
| Answer» B. 30 dB | |
| 1066. |
In a P-N-P transistor, electrons flow |
| A. | into the transistor at the collector only |
| B. | into the transistor at the base and the collector leads |
| C. | out of the transistor at base and collector leads |
| D. | out of the transistor at base, collector as well as emitter leads |
| Answer» C. out of the transistor at base and collector leads | |
| 1067. |
Assertion (A): If we overdrive an amplifier the output signal may get clippedReason (R): To dissipate heat to atmosphere a heat sink is sometimes attached to the case of transistor |
| 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 | |
| 1068. |
Which of the following is not valid in case of bipolars? |
| A. | It has a low input impedance |
| B. | It has high voltage gain |
| C. | It is a current controlled device |
| D. | It is difficult to bias |
| Answer» E. | |
| 1069. |
The bandwidth of an amplifier is BW, of n-stage of such as amplifier are cascaded, the bandwidth will become |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 1070. |
In figure vi is a sinusoidal wave. Which of the following best describes the output v0? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 1071. |
Each of two cascaded stages has a voltage gain of 30. The overall gain is |
| A. | 3 |
| B. | 9 |
| C. | 30 |
| D. | 900 |
| Answer» E. | |
| 1072. |
In figure it is desired that output wave is symmetrical. Then |
| A. | both diodes should be similar and |V1| = |V2| |
| B. | both diodes should be similar |
| C. | |V1| = |V2| |
| D. | either (a) or (b) |
| Answer» B. both diodes should be similar | |
| 1073. |
If 1.5% of the output of an amplifier is feedback positively to the input, the minimum gain required of the amplifier for oscillations to occur, is |
| A. | 16.6 |
| B. | 44.4 |
| C. | 66.6 |
| D. | 75 |
| Answer» D. 75 | |
| 1074. |
The load impedance ZL of a CE amplifier has R and L in series. The phase difference between output and input will be |
| A. | 180° |
| B. | 0 |
| C. | more than 90° but less than 180° |
| D. | more than 180° but less than 270° |
| Answer» E. | |
| 1075. |
In a closed loop non-inverting amplifier, constructed using single break-frequency op-amp, bandwidth with feedback can be written as. (f0 - break frequency, β - gain of the feedback circuit, A - open loop voltage gain, Af - closed loop voltage gain) |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 1076. |
Which coupling produces the minimum interference with frequency response? |
| A. | RC coupling |
| B. | Transformer coupling |
| C. | Direct coupling |
| D. | Impedance coupling |
| Answer» D. Impedance coupling | |
| 1077. |
In applications where __________ input resistance is needed, the JFET is preferred to the bipolar transistor. |
| A. | zero |
| B. | very low |
| C. | low |
| D. | high |
| Answer» E. | |
| 1078. |
A CB amplifier has a = 0.98 and RL = 600 Ω. If IE = 3.5 mA, the current gain is |
| A. | 1 |
| B. | 0.98 |
| C. | 0.98 x 3.5 |
| D. | 3.5/0.98 |
| Answer» C. 0.98 x 3.5 | |
| 1079. |
For an I/p of Vs = 5 sin ωt (assuming ideal diode), circuit shown in the figure will behave as a |
| A. | clipper, sine wave clipped at -2 V |
| B. | clamper, sine wave clamped at -2 V |
| C. | clamper, sine wave clamped at 0 volts |
| D. | clipper, sine wave clipped at 2 V |
| Answer» E. | |
| 1080. |
RECTIFIER : OSCILLATOR :: |
| A. | Capacitance : Inductance |
| B. | Series resonance : Parallel resonance |
| C. | DC : AC |
| D. | Regulation : Efficiency |
| Answer» E. | |
| 1081. |
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 | |
| 1082. |
The ripple factor of a half wave rectifier is more than 2. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» C. May be True or False | |
| 1083. |
In the CE circuit shown in figure the slope of dc load line will be |
| A. | - 1/500 |
| B. | - 1/250 |
| C. | - 1/750 |
| D. | - 1/1000 |
| Answer» B. - 1/250 | |
| 1084. |
The voltage gain of which transistor configuration is less than unity? |
| A. | CB |
| B. | CE |
| C. | CC |
| D. | None |
| Answer» D. None | |
| 1085. |
Which of the following can be used as a buffer amplifier? |
| A. | CE |
| B. | CC |
| C. | CB |
| D. | Both (a) and (c) |
| Answer» C. CB | |
| 1086. |
The dissipation at the collector is in the quiescent state and increases with excitation in the case of a |
| A. | class A series fed Amplifier |
| B. | class A transistor coupled Amplifier |
| C. | class AB amplifier |
| D. | class B amplifier |
| Answer» E. | |
| 1087. |
In a capacitor filter, the time constant RLC should be small. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» C. May be True or False | |
| 1088. |
If the value of C₂ and C₃ are doubled, the oscillation frequency will be |
| A. | quadrupled |
| B. | doubled |
| C. | unchanged |
| D. | halved |
| Answer» D. halved | |
| 1089. |
In a biased JFET (Figure) the shape of the channel is as shown because |
| A. | it is the property of material used |
| B. | the drain end is more reverse biased than source end |
| C. | drain end is more forward biased than source end |
| D. | impurity profile changes with distance |
| Answer» C. drain end is more forward biased than source end | |
| 1090. |
The linear transistor circuits always operate in the |
| A. | saturation |
| B. | cut off |
| C. | active |
| D. | inactive |
| Answer» D. inactive | |
| 1091. |
Aperture circuit produces __________ in sample hold circuit. |
| A. | the total sampling time |
| B. | delay between the instance at which hold command is initiated and the instance at which O/P starts tracking I/P |
| C. | the time taken by O/P to settle within the specified 1% error band, that of the I/P |
| D. | time required by holding capacitor to reach upto the level close to input |
| Answer» C. the time taken by O/P to settle within the specified 1% error band, that of the I/P | |
| 1092. |
A 120 V, 30 Hz source feeds a half wave rectifier circuit through a 4 : 1 step down transformer, the average output voltage is |
| A. | 30 V |
| B. | 13.5 V |
| C. | 10 V |
| D. | 7.07 V |
| Answer» C. 10 V | |
| 1093. |
The emitter follower steps up the impedance by a factor of |
| A. | α |
| B. | β |
| C. | α β |
| D. | α/β |
| Answer» C. α β | |
| 1094. |
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. | |
| 1095. |
Which of the following configuration has low thermal stability? |
| A. | CB |
| B. | CC |
| C. | CE |
| D. | All have identical thermal stability |
| Answer» B. CC | |
| 1096. |
When load is coupled to class A amplifier through transformer, efficiency decreases. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» C. May be True or False | |
| 1097. |
A P-channel MOSFET operating in the enhancement mode is characterized by Vt = - 4 V and IDQ = - 10 mA, when VGSQ = - 5.5 V, what will be VGSQ if IDQ = -15 mA and ID, on = - 16 mA |
| A. | - 2 V |
| B. | 3 V |
| C. | 0.13 V |
| D. | 1.3 V |
| Answer» D. 1.3 V | |
| 1098. |
The A.C. resistance of the emitter diode will be |
| A. | 5.05 Ω |
| B. | 50.5 Ω |
| C. | 505 Ω |
| D. | 5050 Ω |
| Answer» C. 505 Ω | |
| 1099. |
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 | |
| 1100. |
In an LC filter, the ripple factor, |
| A. | increases with load current |
| B. | increases with load resistance |
| C. | remains constant with the load current |
| D. | has the lowest value |
| Answer» E. | |