MCQOPTIONS
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MCQOPTIONS
This section includes 36 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A change in the value of the emitter resistance Re in a differential amplifier? |
| A. | affects the difference mode gain Ad |
| B. | affects the common mode gain Ac |
| C. | affects both Ad and Ac |
| D. | does not effect either Ad and Ac |
| Answer» C. affects both Ad and Ac | |
| 2. |
A 741-type OP-AMP has a gain-bandwidth product of 1MHz. A non-inverting amplifier using this op-amp & having a voltage gain of 20db will exhibit -3db bandwidth of__________? |
| A. | 50 KHz |
| B. | 100KHz |
| C. | 1000/17 KHz |
| D. | 1000/7.07 KHz |
| Answer» C. 1000/17 KHz | |
| 3. |
Thermal runaway is not possible in FET because as the temperature of FET increases%! |
| A. | The mobility decreases |
| B. | The transconductance increases |
| C. | The drain current increases |
| D. | None of the above |
| Answer» B. The transconductance increases | |
| 4. |
In deriving ac equivalent circuit for an amplifier circuit we short circuit%! |
| A. | All resistors |
| B. | All transistors |
| C. | All inductors |
| D. | All capacitors |
| Answer» E. | |
| 5. |
The encapsulation of transistor is necessary for%! |
| A. | Preventing radio interference |
| B. | Preventing photo-emission effects |
| C. | Avoiding loss of free electrons |
| D. | Mechanical ruggedness |
| Answer» E. | |
| 6. |
*/*_A constant current signal across a parallel RLC circuits gives an o/p of 1.4v at the signal frequency of 3.89KHZ and 4.1KHZ. At the frequency of 4KHZ,the o/p voltage will be? |
| A. | 1v |
| B. | 2v |
| C. | 1.4v |
| D. | 2.8v |
| Answer» C. 1.4v | |
| 7. |
*/*_Which of the following statements is false?? |
| A. | Push pull signals are equal and opposite in phase |
| B. | Class AB operation cannot be used for a push pull audio power output phase |
| C. | A push pull output transformer has a centre-tapped primary |
| D. | All of the above |
| Answer» C. A push pull output transformer has a centre-tapped primary | |
| 8. |
*/*_Class AB operation is often used in power large signal) amplifiers in order to? |
| A. | Get maximum efficiency |
| B. | Remove even harmonics |
| C. | Overcome a crossover distortion |
| D. | Reducing collector dissipation |
| Answer» D. Reducing collector dissipation | |
| 9. |
*/*_MOSFET can be used as a? |
| A. | Current controlled capacitor |
| B. | Voltage controlled capacitor |
| C. | Current controlled inductor |
| D. | Voltage controlled inductors |
| Answer» C. Current controlled inductor | |
| 10. |
*/*_Negative feedback in an amplifier? |
| A. | Reduces gain |
| B. | Increase frequency &phase distortion |
| C. | Reduces bandwidth |
| D. | Increases noise |
| Answer» B. Increase frequency &phase distortion | |
| 11. |
*/*_The current gain of a BJT is? |
| A. | gm r0 |
| B. | gm / r0 |
| C. | gm rπ |
| D. | gm /rπ |
| Answer» D. gm /r≈ì√Ñ | |
| 12. |
*/*_In a transistor leakage current mainly depends on? |
| A. | Doping of base |
| B. | Size of emitter |
| C. | Rating of transistor |
| D. | Temperature |
| Answer» E. | |
| 13. |
*/*_Most of the linear ICs are based on the two-transistor differential amplifier because of its? |
| A. | Input voltage dependent linear transfer characteristic |
| B. | High voltage gain |
| C. | High input resistance |
| D. | High CMRR |
| Answer» E. | |
| 14. |
_ To prevent a DC return between source and load, it is necessary to use$? |
| A. | Resistor between source and load |
| B. | Inductor between source and load |
| C. | Capacitor between source and load |
| D. | Either A or B |
| Answer» D. Either A or B | |
| 15. |
__The effective channel length of a MOSFET in a saturation decreases with increase in__ |
| A. | Gate voltage |
| B. | Drain voltage |
| C. | Source voltage |
| D. | Body voltage |
| Answer» C. Source voltage | |
| 16. |
__In an OP-amp differentiator__ |
| A. | The amplitude of output is proportional to rate of change of input |
| B. | The amplitude of output is proportional to input |
| C. | Output occurs when input is finite and constant |
| D. | Polarity of input and output is the same |
| Answer» B. The amplitude of output is proportional to input | |
| 17. |
__Voltage Series (feedback also called series-shunt feedback) results in__ |
| A. | Increase in both input & output impedances |
| B. | Decreases in both input & output impedances |
| C. | Increase in input impedance & decreases in output impedance |
| D. | Decrease in input impedance & increase in output impedance |
| Answer» D. Decrease in input impedance & increase in output impedance | |
| 18. |
__An npn BJT has gm=38mA/v, cµ =10¯14 F, cπ =10¯13F and DC current gain β0=90.For this transistor fT & fβ are__ |
| A. | fT =1.64 x 108 Hz & fβ = 1.47 x 1010 Hz |
| B. | fT =1.47 x 1010 Hz & fβ = 1.64 x 108 Hz |
| C. | fT =1.33 x 1012 Hz & fβ = 1.47 x 1010 Hz |
| D. | fT =1.47 x 1010 Hz & fβ = 1.33 x 1012 Hz |
| Answer» C. fT =1.33 x 1012 Hz & f≈í‚⧠= 1.47 x 1010 Hz | |
| 19. |
__In a common emitter, unbypassed resister provides__ |
| A. | voltage shunt feedback |
| B. | current series feedback |
| C. | negative voltage feedback |
| D. | positive current feedback |
| Answer» D. positive current feedback | |
| 20. |
__The early effect in a bipolar junction transistor is caused by__ |
| A. | Fast turn-on |
| B. | Fast turn-off |
| C. | Large collector-base reverse bias |
| D. | Large emitter-base forward bias |
| Answer» D. Large emitter-base forward bias | |
| 21. |
__The MOSFET switch in its onstate may be considered equivalent to__ |
| A. | Resistor |
| B. | Inductor |
| C. | Capacitor |
| D. | Battery |
| Answer» D. Battery | |
| 22. |
In a p‚Äö√Ö‚à´n junction diode under reverse bias , the magnitude of electric field is maximum at$? |
| A. | The edge of the depletion region on the p-side |
| B. | The edge of the depletion region on the n-side |
| C. | The p‚Äö√Ö‚à´n junction |
| D. | The center of the depletion region on the n-side |
| Answer» D. The center of the depletion region on the n-side | |
| 23. |
In all base driver amplifiers$? |
| A. | ac collector voltage is 180° out of phase with ac base voltage |
| B. | ac emitter voltage is 180° out of phase with ac base voltage |
| C. | ac collector voltage is in phase with ac base voltage |
| D. | none of the above |
| Answer» B. ac emitter voltage is 180¬¨‚àû out of phase with ac base voltage | |
| 24. |
A dc power supply has no-load voltage of 30v,and a full-load voltage of 25v at full-load current of 1A.Its output resistance & load regulation ,respectively are$? |
| A. | 5 Ω & 20 % |
| B. | 25 Ω & 20 % |
| C. | 5 Ω & 16.7 % |
| D. | 25 Ω & 16.7 % |
| Answer» C. 5 ‚Äö√ë¬∂ & 16.7 % | |
| 25. |
An amplifier using an opamp with slew rate SR=1v/µsec has a gain of 40db.if this amplifier has to faithfully amplify sinusoidal signals from dc to 20 KHz without introducing any slew-rate induced distortion, then the input signal level must not exceed$? |
| A. | 795mV |
| B. | 395mV |
| C. | 795 mV |
| D. | 39.5mV |
| Answer» D. 39.5mV | |
| 26. |
The cascade amplifier is a multistage configuration of$? |
| A. | CC-CB |
| B. | CE-CB |
| C. | CB-CC |
| D. | CE-CC |
| Answer» C. CB-CC | |
| 27. |
An n- channel JFET has IDSS=2mA,and Vp=-4v.Its transconductance gm=in mA/V)for an applied gate to source voltage VGS=-2v is$? |
| A. | 0.25 |
| B. | 0.5 |
| C. | 0.75 |
| D. | 1 |
| Answer» C. 0.75 | |
| 28. |
A differential amplifier is invariably used in the i/p stage of all OP-amps.This is dome basically to provide the OP-amps with a very high$? |
| A. | CMRR |
| B. | Bandwidth |
| C. | Slew rate |
| D. | Open-loop gain |
| Answer» B. Bandwidth | |
| 29. |
Introducing a resistor in the emitter of a common amplifier stabilizes the dc operating point against variations in$? |
| A. | Only the temperature |
| B. | only the β of the transistor |
| C. | Both Temperature & β |
| D. | None of the above |
| Answer» D. None of the above | |
| 30. |
Three identical amplifiers with each one having a voltage gain of 50,input resistance of 1KΩ & output resistance of 250, are cascaded. The open circuit voltage gain of combined amplifier is$ |
| A. | 49dB |
| B. | 51dB |
| C. | 98dB |
| D. | 102dB |
| Answer» D. 102dB | |
| 31. |
Which of the following is not associated with a p-n junction |
| A. | Junction capacitance |
| B. | Charge storage capacitance |
| C. | Depletion capacitance |
| D. | Channel length modulation |
| Answer» E. | |
| 32. |
A 741-type OP-amp has a gain-bandwidth product of 1MHz.A non-inverting amplifier using this opamp & having a voltage gain of 20db will exhibit -3db bandwidth of |
| A. | 50 KHz |
| B. | 100 KHz |
| C. | 1000/17 KHz |
| D. | 1000/7.07 KHz |
| Answer» C. 1000/17 KHz | |
| 33. |
The action of JFET in its equivalent circuit can best be represented as a |
| A. | Current controlled Current source |
| B. | Current controlled voltage source |
| C. | Voltage controlled voltage source |
| D. | voltage controlled current source |
| Answer» E. | |
| 34. |
Asource follower using an FET usually has a voltage gain which is |
| A. | Greater than +100 |
| B. | Slightly less than unity but positive |
| C. | Exactly unity but negative |
| D. | About -10 |
| Answer» B. Slightly less than unity but positive | |
| 35. |
If=0.98, Ico=6µA and Iβ=100µA for a transistor,then the value of Ic will be# |
| A. | 2.3mA |
| B. | 3.2mA |
| C. | 4.6mA |
| D. | 5.2mA |
| Answer» E. | |
| 36. |
An amplifier without feedback has a voltage gain of 50,input resistance os 1 KΩ & Output resistance of 2.5KΩ.The input resistance of the current shunt negative feedback amplifier using the above amplifier with a feedbacik factor of 0.2 is# |
| A. | 1/11KΩ |
| B. | 1/5KΩ |
| C. | 5KΩ |
| D. | 11KΩ |
| Answer» B. 1/5K‚Äö√ë¬∂ | |