MCQOPTIONS
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MCQOPTIONS
This section includes 60 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. |
The use of negative feedback |
| A. | reduces the voltage gain of an Op-amp |
| B. | makes the Op-amp oscillate |
| C. | makes linear operation possible |
| D. | A and B both |
| Answer» E. | |
| 2. |
A differential amplifier has a differential gain of 20,000. CMRR=80dB. The common mode gain is given by |
| A. | 2 |
| B. | 1 |
| C. | 1/2 |
| D. | 0 |
| Answer» B. 1 | |
| 3. |
The tail current of a differential amplifier is . |
| A. | half of either collector current |
| B. | equal to either collector current |
| C. | two times either collector current |
| D. | equal to the difference in base currents |
| Answer» D. equal to the difference in base currents | |
| 4. |
With zero volts on both inputs, an OP-amp ideally should have an output ___________ |
| A. | equal to the positive supply voltage |
| B. | equal to the negative supply voltage |
| C. | equal to zero |
| D. | equal to CMRR |
| Answer» D. equal to CMRR | |
| 5. |
A differential amplifier is invariably used in the i/p stage of all OP-amps. This is done basically to provide the OP-amps with a very high |
| A. | CMMR |
| B. | Bandwidth |
| C. | Slew rate |
| D. | Open-loop gain |
| Answer» D. Open-loop gain | |
| 6. |
A differential amplifier ___________ |
| A. | is a part of an Op-amp |
| B. | has one input and one output |
| C. | has two outputs |
| D. | A and B both |
| Answer» E. | |
| 7. |
The common mode voltage gain is |
| A. | smaller than differentail voltage gain |
| B. | equal to differential voltage gain |
| C. | greater than differential voltage gain |
| D. | none of the above |
| Answer» B. equal to differential voltage gain | |
| 8. |
The node voltage at the top of the til resistor is closes to ___________ |
| A. | collector supply voltage |
| B. | zero |
| C. | emitter supply voltage |
| D. | tail current times base resistance |
| Answer» C. emitter supply voltage | |
| 9. |
A certain noninverting amplifier has Ri of 1 kΩ and Rf of 100 kΩ. The closed-loop voltage gain is |
| A. | 100000 |
| B. | 1000 |
| C. | 101 |
| D. | 100 |
| Answer» D. 100 | |
| 10. |
A 741-Type OP-amp has a gain-bandwith product of 1MHz. A non-inverting amplifier using this opamp & having a voltage gain of 20db will exhibit -3db bandwidth of |
| A. | 50KHz |
| B. | 100KHz |
| C. | 1000/17KHz |
| D. | 1000/7.07KHz |
| Answer» B. 100KHz | |
| 11. |
The input impedance of a differential amplifier equals r'e times |
| A. | ß |
| B. | RE |
| C. | RC |
| D. | 2ß |
| Answer» E. | |
| 12. |
How many OP-amps are required to implement this equation |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 1 |
| Answer» E. | |
| 13. |
The differential voltage gain of a differential amplifier is equal to RC divided by . |
| A. | r'e |
| B. | r'e/2 |
| C. | 2r'e |
| D. | RE |
| Answer» D. RE | |
| 14. |
The tail current in a differential amplifier equals . |
| A. | difference between two emitter currents |
| B. | sum of two emitter currents |
| C. | collector current divided by current gain |
| D. | collector voltage divided by collector resistance |
| Answer» C. collector current divided by current gain | |
| 15. |
A certain inverting amplifier has a closed-loop voltage gain of 25. The OP-amp has an open-loop voltage gain of 100,000. If an OP-amp with an open-loop voltage gain of 200,000 is substituted in the arrangement, the closed-loop gain |
| A. | doubles |
| B. | drops to 12.5 |
| C. | remains at 25 |
| D. | increases slightly |
| Answer» D. increases slightly | |
| 16. |
Of the values listed, the most realistic value for open-loop voltage gain of an OP-amp is |
| A. | 1 |
| B. | 2000 |
| C. | 80 dB |
| D. | 100000 |
| Answer» E. | |
| 17. |
The common mode voltage gain of a differential amplifier is equal to RC divided by |
| A. | re |
| B. | 2re |
| C. | re/2 |
| D. | 2RE |
| Answer» E. | |
| 18. |
For an OP-amp with negative feedback, the output is . |
| A. | equal to the input |
| B. | increased |
| C. | fed back to the inverting input |
| D. | fed back to the noninverting input |
| Answer» D. fed back to the noninverting input | |
| 19. |
The output of a particular OP-amp increases 8V in 12µs. The slew rate is |
| A. | 90 V/µs |
| B. | 0.67 V/µs |
| C. | 1.5 V/µs |
| D. | none of these |
| Answer» C. 1.5 V/µs | |
| 20. |
A voltage follower ___________ |
| A. | has a voltage gain of 1 |
| B. | is noninverting |
| C. | has no feedback resistor |
| D. | has all of these |
| Answer» E. | |
| 21. |
Negative feedback ___________ |
| A. | increases the input and output impedances |
| B. | increases the input impedance and bandwidth |
| C. | decreases the output impedance and bandwidth |
| D. | does not affect impedance or bandwidth |
| Answer» C. decreases the output impedance and bandwidth | |
| 22. |
When a differential amplifier is operated single-ended, ___________ |
| A. | the output is grounded |
| B. | one input is grounded and signal is applied to the other |
| C. | both inputs are connected together |
| D. | the output is not inverted |
| Answer» C. both inputs are connected together | |
| 23. |
In the differential voltage gain & the common mode voltage gain of a differential amplifier are 48db & 2db respectively, then its common mode rejection ratio is |
| A. | 23dB |
| B. | 25dB |
| C. | 46dB |
| D. | 50dB |
| Answer» D. 50dB | |
| 24. |
The OP-amp can amplify |
| A. | c. signals only |
| B. | d.c. signals only |
| C. | both a.'and d.'signals |
| D. | neither 'c. nor a.c. signals |
| Answer» D. neither 'c. nor a.c. signals | |
| 25. |
When a number of stages are connected in parallel, the overall gain is the product of the individual stage gains |
| A. | True |
| B. | False |
| Answer» C. | |
| 26. |
The differential gain is |
| A. | very high |
| B. | very low |
| C. | dependent on input voltage |
| D. | about 100 |
| Answer» B. very low | |
| 27. |
In differential-mode, ___________ |
| A. | opposite polarity signals are applied to the inputs |
| B. | the gain is one |
| C. | the outputs are of different amplitudes |
| D. | only one supply voltage is used |
| Answer» B. the gain is one | |
| 28. |
The input offset current equals the ___________ |
| A. | difference between two base currents |
| B. | average of two base currents |
| C. | collector current divided by current gain |
| D. | none of these |
| Answer» B. average of two base currents | |
| 29. |
For an OP-amp having differential gain Av and common mode gain Ac the CMRR is given by |
| A. | Av + Ac |
| B. | Av / Ac |
| C. | 1 + (Av / Ac) |
| D. | Ac / Av |
| Answer» C. 1 + (Av / Ac) | |
| 30. |
A certain OP-amp has bias currents of 50 µA. The input offset current is |
| A. | 700 nA |
| B. | 99.3 µA |
| C. | 49.7 µA |
| D. | none of these |
| Answer» B. 99.3 µA | |
| 31. |
The input stage of an OP-amp is usually a ___________ |
| A. | differential amplifier |
| B. | class B push-pull amplifier |
| C. | CE amplifier |
| D. | swamped amplifier |
| Answer» B. class B push-pull amplifier | |
| 32. |
A common mode signal is applied to ___________ |
| A. | the noninverting input |
| B. | the inverting input |
| C. | both iputs |
| D. | top of the tail resistor |
| Answer» D. top of the tail resistor | |
| 33. |
OP-amp circuits may be cascaded without changing their input output relationships |
| A. | True |
| B. | False |
| Answer» B. False | |
| 34. |
In the common mode, ___________ |
| A. | both inputs are grounded |
| B. | the outputs are connected together |
| C. | an identical signal appears on both the inputs |
| D. | the output signal are in-phase |
| Answer» D. the output signal are in-phase | |
| 35. |
An OPAMP has a slew rate of 5 V/μ S .The largest sine wave O/P voltage possible at a frequency of 1 MHZ is[Hint: Slew rate is defined as the max. rate of change of output voltage. Its unit is V/μS.] |
| A. | 10 volts |
| B. | 5 volts |
| C. | 5/1 volts |
| D. | 5/2 volts |
| Answer» E. | |
| 36. |
Current cannot flow to ground through . |
| A. | a mechanical ground |
| B. | an a.c. ground |
| C. | a virtual ground |
| D. | an ordinary ground |
| Answer» D. an ordinary ground | |
| 37. |
An amplifier using an opamp with slew rate SR=1v/sec has a gain of 40db.If this amplifier has to faithfully amplify sinusoidal signals from dc to 20KHz without introducing any slew-rate induced distortion, then the input signal level exceed |
| A. | 795mV |
| B. | 395mV |
| C. | 795mV |
| D. | 39.5mV |
| Answer» D. 39.5mV | |
| 38. |
The common mode gain is ___________ |
| A. | very high |
| B. | very low |
| C. | always unity |
| D. | unpredictable |
| Answer» C. always unity | |
| 39. |
In the differential voltage gain & the common mode voltage gain of a differential amplifier are 48db & 2db respectively, then its common mode rejection ratio is |
| A. | 23dB |
| B. | 25dB |
| C. | 46dB |
| D. | 50dB |
| Answer» C. 46dB | |
| 40. |
A differential amplifier is invariably used in the i/p stage of all op-amps. This is done basically to provide the op-amps with a very high |
| A. | CMMR |
| B. | bandwidth |
| C. | slew rate |
| D. | open-loop gain |
| Answer» D. open-loop gain | |
| 41. |
Assume that the op-amp of the fig. is ideal. If Vi is a triangular wave, then V0 will be |
| A. | square wave |
| B. | Triangular wave |
| C. | . Parabolic wave |
| D. | Sine wave |
| Answer» E. | |
| 42. |
An opamp has a slew rate of 5V/ S. the largest sine wave o/p voltage possible at a frequency of 1MHz is |
| A. | 10 V |
| B. | 5 V |
| C. | 5V |
| D. | 5/2 V |
| Answer» B. 5 V | |
| 43. |
The approximate input impedance of the opamp circuit which has Ri=10k, Rf=100k, RL=10k |
| A. | ∞ |
| B. | 120k |
| C. | 110k |
| D. | . 10k |
| Answer» D. . 10k | |
| 44. |
The ideal OP-AMP has the following characteristics |
| A. | . Ri=∞,A=∞,R0=0 |
| B. | Ri=0,A=∞,R0=0 |
| C. | Ri=∞,A=∞,R0=∞ |
| D. | Ri=0,A=∞,R0=∞ |
| Answer» B. Ri=0,A=∞,R0=0 | |
| 45. |
An amplifier using an opamp with slew rate SR=1v/sec has a gain of 40dB.If this amplifier has to faithfully amplify sinusoidal signals from dc to 20KHz without introducing any slew-rate induced distortion, then the input signal level exceed |
| A. | 795mV |
| B. | 395mV |
| C. | 795mV |
| D. | 39.5mV |
| Answer» D. 39.5mV | |
| 46. |
A 741-Type OP-AMP has a gain-bandwith product of 1MHz. A non-inverting amplifier using this opamp & having a voltage gain of 20db will exhibit -3db bandwidth of |
| A. | 50KHz |
| B. | 100KHz |
| C. | 1000/17KHz |
| D. | 1000/7.07KHz |
| Answer» B. 100KHz | |
| 47. |
In the above circuit the current ix is |
| A. | 0.6A |
| B. | 0.5A |
| C. | 0.2A |
| D. | 1/12A |
| Answer» C. 0.2A | |
| 48. |
The output voltage Vo of the above circuit is |
| A. | 6V |
| B. | -5V |
| C. | 1.2V |
| D. | -0.2V |
| Answer» C. 1.2V | |
| 49. |
When a step-input is given to an op-amp integrator, the output will be |
| A. | a ramp. |
| B. | a sinusoidal wave. |
| C. | a rectangular wave. |
| D. | a triangular wave with dc bias |
| Answer» B. a sinusoidal wave. | |
| 50. |
The two input terminals of an opamp are labeled as |
| A. | High and low |
| B. | Positive and negative |
| C. | Inverting and non inverting |
| D. | Differential ans non differential |
| Answer» D. Differential ans non differential | |