MCQOPTIONS
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MCQOPTIONS
This section includes 53 Mcqs, each offering curated multiple-choice questions to sharpen your Active Filter Circuits knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A three-stage op-amp can have a maximum phase lag of ________°. |
| A. | –180 |
| B. | –90 |
| C. | none of the above |
| D. | –270 |
| Answer» E. | |
| 2. |
The magnitude of closed-loop voltage gain ( A cl ) of an inverting amplifier equals: |
| A. | the ratio of the input resistance to the feedback resistance |
| B. | the open-loop voltage gain A ol |
| C. | the feedback resistance divided by the input resistance |
| D. | the input resistance |
| Answer» D. the input resistance | |
| 3. |
In an open-loop op-amp circuit, whenever the inverting input (–) is negative relative to the noninverting input (+), the output will: |
| A. | swing negative |
| B. | close the loop |
| C. | be balanced |
| D. | swing positive |
| Answer» E. | |
| 4. |
Input impedance [ Z in (I)] of an inverting amplifier is approximately equal to: |
| A. | R i |
| B. | R f + R i |
| C. | ? |
| D. | R f – R i |
| Answer» B. R f + R i | |
| 5. |
If a noninverting amplifier has an R IN of 1000 ohms and an R FB of 2.5 kilohms, what is the R IN voltage when 1.42 mV is applied to the correct input? |
| A. | 3.5 mV |
| B. | ground |
| C. | 1.42 mV |
| D. | 0.56 mV |
| Answer» D. 0.56 mV | |
| 6. |
If ground is applied to the (+) terminal of an inverting op-amp, the (–) terminal will: |
| A. | not need an input resistor |
| B. | be virtual ground |
| C. | have high reverse current |
| D. | not invert the signal |
| Answer» C. have high reverse current | |
| 7. |
The open-loop voltage gain ( A ol ) of an op-amp is the |
| A. | external voltage gain the device is capable of |
| B. | internal voltage gain the device is capable of |
| C. | most controlled parameter |
| D. | same as A cl |
| Answer» C. most controlled parameter | |
| 8. |
Open-loop voltage gain of an op-amp can range up to ________. |
| A. | 10,000 |
| B. | 50,000 |
| C. | 100,000 |
| D. | 200,000 |
| Answer» E. | |
| 9. |
Which of the following is (are) the result of gain reduction by a feedback? |
| A. | The amplifier voltage gain is a more stable and precise value. |
| B. | The input impedance of the circuit is increased over that of the op-amp alone. |
| C. | The output impedance is reduced over that of the op-amp alone. |
| D. | All of the above |
| Answer» E. | |
| 10. |
At what input voltage level does the output voltage level become numerically equal to the value of the common-mode gain of the amplifier? |
| A. | V i1 = –V i2 = 0.25 V |
| B. | V i1 = –V i2 = 0.50 V |
| C. | V i1 = –V i2 = 0.75 V |
| D. | V i1 = –V i2 = 1.00 V |
| Answer» C. V i1 = –V i2 = 0.75 V | |
| 11. |
What is the level of the current through the amplifier input(s) to ground in an op-amp? |
| A. | Virtually zero |
| B. | 1.7 mA |
| C. | 2.8 mA |
| D. | 3.3 mA |
| Answer» B. 1.7 mA | |
| 12. |
Calculate the input voltage if R 1 = 100 , R f = 1 k , and V out = 550 mV. |
| A. | –50 mV |
| B. | –5 mV |
| C. | 550 mV |
| D. | 50 mV |
| Answer» E. | |
| 13. |
The midrange open-loop gain of an op-amp is 135 dB. With negative feedback this gain is reduced to 72 dB. The closed-loop gain is |
| A. | 135 dB. |
| B. | 72 dB. |
| C. | 207 dB. |
| D. | 63 dB. |
| Answer» C. 207 dB. | |
| 14. |
What is the difference voltage if the inputs are an ideal in-phase signal? |
| A. | The differential gain times twice the input signal. |
| B. | The differential gain times the input signal. |
| C. | The common-mode gain times twice the input signal. |
| D. | The common-mode gain times the input signal. |
| Answer» E. | |
| 15. |
The ________ amplifier configuration has the highest input impedance and the lowest output impedance of the three basic op-amp configurations. |
| A. | non-inverting |
| B. | inverting |
| C. | voltage-follower |
| D. | - |
| Answer» D. - | |
| 16. |
A(n) ________ amplifier configuration has an input impedance approximately equal to the input resistor R i and an output impedance approximately equal to the output impedance of the op-amp itself. |
| A. | non-inverting |
| B. | inverting |
| C. | voltage-follower |
| D. | - |
| Answer» C. voltage-follower | |
| 17. |
The ________ is the voltage gain of an op-amp with external feedback. |
| A. | A ol |
| B. | A cl |
| C. | A v |
| D. | - |
| Answer» C. A v | |
| 18. |
What is the cutoff frequency of an op-amp if the unity-gain frequency is 1.5 MHz and the open-loop gain is 100,000? |
| A. | 5 Hz |
| B. | 10 Hz |
| C. | 15 Hz |
| D. | 20 Hz |
| Answer» D. 20 Hz | |
| 19. |
In the differential amplifier circuit, which of the following terminals are connected together? |
| A. | Bases |
| B. | Collectors |
| C. | One base to another collector |
| D. | Emitters |
| Answer» E. | |
| 20. |
Which of the following circuits is referred to as a BiMOS circuit? |
| A. | Bipolar and FET |
| B. | Bipolar and MOSFET |
| C. | Opposite-type MOSFETs |
| D. | None of the above |
| Answer» C. Opposite-type MOSFETs | |
| 21. |
What is the scale multiplier (factor) of a basic integrator? |
| A. | R / C |
| B. | C / R |
| C. | –RC |
| D. | –1 / RC |
| Answer» E. | |
| 22. |
An RC network has R = 500 k and C = 10 pF. Find the value of f c . |
| A. | 31831 Hz |
| B. | 31.831 kHz |
| C. | 0.031831 MHz |
| D. | all of the above |
| Answer» E. | |
| 23. |
It takes an op-amp 22 s to change its output from –15 V to +15 V. Determine the slew rate. |
| A. | 1.36 V/ s |
| B. | 0.68 V/ s |
| C. | –0.68 V/ s |
| D. | cannot determine |
| Answer» B. 0.68 V/ s | |
| 24. |
Negative feedback added to an op-amp ________ the bandwidth and ________ the gain. |
| A. | increases, increases |
| B. | increases, decreases |
| C. | decreases, decreases |
| D. | decreases, increases |
| Answer» C. decreases, decreases | |
| 25. |
In which of the following operations is the resulting output signal of the differential amplifier near zero? |
| A. | Single-ended |
| B. | Double-ended |
| C. | Common-mode |
| D. | None of the above |
| Answer» D. None of the above | |
| 26. |
What is the voltage gain of the unity follower? |
| A. | 0 |
| B. | 1 |
| C. | –1 |
| D. | Infinity |
| Answer» C. –1 | |
| 27. |
A(n) ________ amplifier configuration has a higher input impedance and a lower output impedance than the op-amp itself. |
| A. | non-inverting |
| B. | inverting |
| C. | voltage-follower |
| D. | - |
| Answer» B. inverting | |
| 28. |
Which of the following circuit conditions affect(s) the output offset voltage of an op-amp? |
| A. | An input offset voltage, V IO |
| B. | An input offset current, I IO |
| C. | Both an input offset voltage, V IO and an input offset current, I IO |
| D. | None of the above |
| Answer» D. None of the above | |
| 29. |
The input offset voltage drift is a parameter directly related to V OS and ________. |
| A. | I D |
| B. | power dissipation |
| C. | temperature |
| D. | phase shift |
| Answer» D. phase shift | |
| 30. |
What is the difference voltage if the inputs are an ideal opposite signal? |
| A. | The differential gain times twice the input signal. |
| B. | The differential gain times the input signal. |
| C. | The common-mode gain times twice the input signal. |
| D. | The common-mode gain times the input signal. |
| Answer» B. The differential gain times the input signal. | |
| 31. |
Calculate the output impedance of an inverting op-amp using the 741 op-amp (r o = 75 , A OL = 200 V/mV) if R 1 = 100 and R f = 1 k . |
| A. | 0.011 |
| B. | 0.00375 |
| C. | 0.0375 |
| D. | 0.375 |
| Answer» C. 0.0375 | |
| 32. |
What is the level of the roll-off in most op-amps? |
| A. | –6 dB / decade |
| B. | –20 dB / octave |
| C. | –6 dB / decade or –20 dB / octave |
| D. | –20 dB / decade or –6 dB / octave |
| Answer» E. | |
| 33. |
A practical op-amp has very ________ input impedance, very ________ output impedance, very ________ open-loop voltage gain, and a ________ bandwidth. |
| A. | high, low, high, wide |
| B. | high, high, low, narrow |
| C. | low, high, high, wide |
| D. | low, low, low, wide |
| Answer» B. high, high, low, narrow | |
| 34. |
At what input voltage level does the output voltage level become numerically equal to the value of the differential gain of the amplifier? |
| A. | V i1 = –V i2 = 0.25 V |
| B. | V i1 = –V i2 = 0.50 V |
| C. | V i1 = –V i2 = 0.75 V |
| D. | V i1 = –V i2 = 1.00 V |
| Answer» C. V i1 = –V i2 = 0.75 V | |
| 35. |
The maximum rate of change of the output voltage in response to a step input voltage is the ________ of an op-amp. |
| A. | time constant |
| B. | maximum frequency |
| C. | slew rate |
| D. | static discharge |
| Answer» D. static discharge | |
| 36. |
If R f = R 1 , the voltage gain is ________. |
| A. | 1 |
| B. | –1 |
| C. | 10 |
| D. | very small |
| Answer» C. 10 | |
| 37. |
Calculate the output voltage if R 1 = R 2 = R 3 = 100 , R f = 1 k , and V 1 = V 2 = V 3 = 50 mV. |
| A. | –1.5 V |
| B. | 1.5 V |
| C. | 0.5 V |
| D. | –0.5 V |
| Answer» B. 1.5 V | |
| 38. |
What is the slew rate of an op-amp if the output voltages change from 2 V to 3 V in 0.2 ms? |
| A. | 5 V/ms |
| B. | 3 V/ms |
| C. | 2 V/ms |
| D. | 1 V/ms |
| Answer» B. 3 V/ms | |
| 39. |
An IC unit made using both ________ and ________ transistors is called a ________ circuit. |
| A. | bipolar, MOSFET, BiFET |
| B. | bipolar, MOSFET, BiMOS |
| C. | TTL, MOSFET, TailFET |
| D. | - |
| Answer» C. TTL, MOSFET, TailFET | |
| 40. |
A certain op-amp has an open-loop voltage gain of 150,000. What is this gain expressed in dB? |
| A. | 51.7 dB |
| B. | 103.5 dB |
| C. | 150,000 dB |
| D. | 5.18 dB |
| Answer» C. 150,000 dB | |
| 41. |
An RC network has R = 47 k and C = 0.22 F. What is the cutoff frequency? |
| A. | 154 Hz |
| B. | 1540 Hz |
| C. | 1.54 Hz |
| D. | 15.4 Hz |
| Answer» E. | |
| 42. |
This circuit is referred to as a(n) ________. |
| A. | inverting amplifier |
| B. | noninverting amplifier |
| C. | differentiator |
| D. | integrator |
| Answer» E. | |
| 43. |
Calculate the overall voltage gain of the circuit if R 1 = 100 and R f = 1 k . |
| A. | –1 |
| B. | –10 |
| C. | 11 |
| D. | 9 |
| Answer» D. 9 | |
| 44. |
What is the open-loop gain of an op-amp at the gain-bandwidth product of the op-amp? |
| A. | 200,000 |
| B. | 50,000 |
| C. | 200 |
| D. | 1 |
| Answer» E. | |
| 45. |
The summing amplifier contains an inverting amplifier. |
| A. | True |
| B. | False |
| C. | - |
| D. | - |
| Answer» B. False | |
| 46. |
What is the difference output voltage of any signals applied to the input terminals? |
| A. | The differential gain times the difference input voltage. |
| B. | The common-mode gain times the common input voltage. |
| C. | The sum of the differential gain times the difference input voltage and the common-mode gain times the common input voltage. |
| D. | The difference of the differential gain times the difference input voltage and the common-mode gain times the common input voltage. |
| Answer» D. The difference of the differential gain times the difference input voltage and the common-mode gain times the common input voltage. | |
| 47. |
A three-stage op-amp can have a maximum phase lag of ________°. |
| A. | –180 |
| B. | –90 |
| C. | –270 |
| D. | none of the above |
| Answer» D. none of the above | |
| 48. |
An op-amp has an open-loop gain of 75,000 and a cutoff frequency of 100 Hz. At 1 kHz the open-loop gain is down by |
| A. | 10 dB. |
| B. | 6 dB. |
| C. | 20 dB. |
| D. | 3 dB. |
| Answer» D. 3 dB. | |
| 49. |
What is the level of the voltage between the input terminals of an op-amp? |
| A. | Virtually zero |
| B. | 5 V |
| C. | 18 V |
| D. | 22 V |
| Answer» B. 5 V | |
| 50. |
An op-amp has an open-loop gain of 100,000 and a cutoff frequency of 40 Hz. Find the open-loop gain at a frequency of 30 Hz. |
| A. | 800 |
| B. | 8,000 |
| C. | 80,000 |
| D. | 100,000 |
| Answer» E. | |