MCQOPTIONS
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MCQOPTIONS
This section includes 111 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. |
Typically, a unijunction transistor has a stand-off ratio from ________ to ________. |
| A. | 0.0, 0.2 |
| B. | 0.2, 0.4 |
| C. | 0.4, 0.6 |
| D. | 0.6, 0.8 |
| Answer» D. 0.6, 0.8 | |
| 2. |
________ is a frequency-determining component in a unijunction oscillator. |
| A. | Total resistance |
| B. | Total capacitance |
| C. | Intrinsic stand-off ratio |
| D. | All of the above |
| Answer» E. | |
| 3. |
At the series-resonant frequency, the amount of positive feedback is ________. |
| A. | very large |
| B. | large |
| C. | small |
| D. | very small |
| Answer» B. large | |
| 4. |
The parallel-resonant impedance of a crystal oscillator is ________. |
| A. | very low |
| B. | low |
| C. | medium |
| D. | very high |
| Answer» E. | |
| 5. |
The series-resonant impedance of a crystal oscillator is ________. |
| A. | very low |
| B. | low |
| C. | medium |
| D. | very high |
| Answer» B. low | |
| 6. |
Since the crystal losses represented by R are small, the equivalent crystal Q (quality factor) is ________. |
| A. | very low |
| B. | low |
| C. | medium |
| D. | high |
| Answer» E. | |
| 7. |
In the Colpitts oscillator, the elements X1 and X2 are ________ and X3 is a(n) ________. |
| A. | inductors, capacitor |
| B. | capacitors, inductor |
| C. | capacitors, resistor |
| D. | inductors, resistor |
| Answer» C. capacitors, resistor | |
| 8. |
Crystal oscillators are used whenever a(n) ________ level of stability is required. |
| A. | lower |
| B. | average |
| C. | greater |
| D. | None of the above |
| Answer» D. None of the above | |
| 9. |
In a Hartley oscillator, the elements X1 and X2 are ________ and X3 is a(n) ________. |
| A. | inductors, capacitor |
| B. | capacitors, inductor |
| C. | capacitors, resistor |
| D. | inductors, resistor |
| Answer» B. capacitors, inductor | |
| 10. |
In the Colpitts oscillator, the frequency is determined by ________ . |
| A. | resistance only |
| B. | inductance only |
| C. | capacitance only |
| D. | both inductance and a capacitance |
| Answer» E. | |
| 11. |
In the Wien bridge oscillator with R1 = R2 = R and C1 = C2 = C, a ratio of R3 to R4 will provide sufficient loop gain for the circuit to oscillate. |
| A. | 0 |
| B. | 0.5 |
| C. | 1 |
| D. | 2 |
| Answer» E. | |
| 12. |
In the phase-shift oscillator, the operating frequency is determined by ________. |
| A. | resistance only |
| B. | capacitance only |
| C. | LC combinations |
| D. | RC combinations |
| Answer» E. | |
| 13. |
In the phase-shift oscillator, the gain of the amplifier stage must be ________. |
| A. | 0 |
| B. | less than 29 |
| C. | greater than 29 |
| D. | [D]. |
| Answer» D. [D]. | |
| 14. |
In practice, A is made ________ and the system is started oscillating by amplifying noise voltage, which is always present. |
| A. | greater than 1 |
| B. | smaller than 1 |
| C. | equal to 1 |
| D. | None of the above |
| Answer» B. smaller than 1 | |
| 15. |
In the Barkhausen criterion, the loop gain A is equal to ________. |
| A. | [A]. |
| B. | 200,000 |
| C. | 0 |
| D. | 1 |
| Answer» E. | |
| 16. |
An amplifier is stable if the absolute magnitude of A is ________. |
| A. | [A]. |
| B. | less than 1 |
| C. | greater than 1 |
| D. | None of the above |
| Answer» C. greater than 1 | |
| 17. |
In a Nyquist plot, as the frequency increases, the phase shift between input and output signals ________. |
| A. | remains the same |
| B. | decreases |
| C. | increases |
| D. | None of the above |
| Answer» D. None of the above | |
| 18. |
An amplifier with negative feedback has ________ bandwidth than (as) the amplifier without feedback. |
| A. | the same |
| B. | less |
| C. | more |
| D. | None of the above |
| Answer» D. None of the above | |
| 19. |
A feedback amplifier has a ________ upper 3-dB frequency and a ________ lower 3-dB frequency compared to an amplifier without feedback. |
| A. | smaller, higher |
| B. | higher, smaller |
| C. | smaller, smaller |
| D. | higher, higher |
| Answer» C. smaller, smaller | |
| 20. |
With feedback, , the overall gain of the circuit is reduced by a factor ________ where A is the gain without the feedback. |
| A. | [A]. |
| B. | A |
| C. | A |
| D. | 1 + A |
| Answer» E. | |
| 21. |
What is the gain at the origin of the Nyquist plot? |
| A. | Zero |
| B. | A negative value |
| C. | A positive value |
| D. | Undefined |
| Answer» B. A negative value | |
| 22. |
Voltage feedback connections tend to ________ the output impedance. Current feedback connections tend to ________ the output impedance. |
| A. | decrease, increase |
| B. | increase, decrease |
| C. | increase, increase |
| D. | decrease, decrease |
| Answer» B. increase, decrease | |
| 23. |
Positive feedback results in ________. |
| A. | decreased voltage gain |
| B. | increased voltage gain |
| C. | oscillation in the circuit |
| D. | None of the above |
| Answer» D. None of the above | |
| 24. |
Negative feedback results in ________. |
| A. | decreased voltage gain |
| B. | increased voltage gain |
| C. | oscillation in the circuit |
| D. | None of the above |
| Answer» B. increased voltage gain | |
| 25. |
Series-feedback connections tend to ________ the input resistance. Shunt feedback connections tend to ________ the input resistance. |
| A. | decrease, increase |
| B. | increase, decrease |
| C. | increase, increase |
| D. | decrease, decrease |
| Answer» C. increase, increase | |
| 26. |
Calculate the value of C1 = C2 for the Wien bridge oscillator to operate at a frequency of 20 kHz. Assume R1 = R2 = 50 k and R3 = 3R4 = 600? |
| A. | 1.59 pF |
| B. | 15.9 pF |
| C. | 159 pF |
| D. | 1.59 nF |
| Answer» D. 1.59 nF | |
| 27. |
Calculate the resonant frequency of this Wien bridge oscillator if R1 = 25 k, R2 = 40 k, C1 = 0.001 F, and C2 = 0.002 F. |
| A. | 1560.3 Hz |
| B. | 1779.4 Hz |
| C. | 3120.7 Hz |
| D. | 3558.8 Hz |
| Answer» E. | |
| 28. |
In the IC phase-shift oscillator, what should the ratio of feedback resistor Rf to R1 be? |
| A. | Zero |
| B. | Greater than –29 |
| C. | Less than 29 |
| D. | Any value |
| Answer» C. Less than 29 | |
| 29. |
Given gm = 5000 S, rd = 40 k, R = 10 k, and A = 35. Determine the value of RD for oscillator operation at 1 kHz. |
| A. | 8.05 k |
| B. | 8.48 k |
| C. | 10.8 k |
| D. | 12.3 k |
| Answer» C. 10.8 k | |
| 30. |
The amplifier is unstable if the Nyquist curve plotted encloses (encircles) the –1 point, and it is stable otherwise. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 31. |
Referring to this figure, calculate the voltage gain with the feedback for the following circuit values: RD = 4 k, RS = 1 k, RF = 15 k, and gm = 5000 μS. |
| A. | –11.2 |
| B. | –8.57 |
| C. | –6.75 |
| D. | –3.25 |
| Answer» C. –6.75 | |
| 32. |
Referring to this figure, calculate the voltage gain without feedback for the following circuit values: RD = 4 k, RS = 1 k, RF = 15 k, and gm = 5000 μS. |
| A. | –20.0 |
| B. | –21.5 |
| C. | –23.5 |
| D. | –25.5 |
| Answer» B. –21.5 | |
| 33. |
Referring to this figure, calculate the voltage gain with feedback Avf. |
| A. | –4.85 |
| B. | –4.20 |
| C. | –4.17 |
| D. | –4.00 |
| Answer» D. –4.00 | |
| 34. |
Referring to this figure, calculate the amplification gain where the op-amp gain (A) is 200,000, R1 = 1.5 k, and R2 = 400 . |
| A. | 4.25 |
| B. | 4.5 |
| C. | 4.75 |
| D. | 5 |
| Answer» D. 5 | |
| 35. |
Referring to this figure, calculate the amplification gain with feedback for the following circuit values: R1 = 80 k, R2 = 20 k, Ro = 10 k, RD = 61 k, and gm = 4000 μS. |
| A. | –4.36 |
| B. | –4.25 |
| C. | –6.35 |
| D. | –20.85 |
| Answer» B. –4.25 | |
| 36. |
An amplifier with a gain of –500 and a feedback of = –0.1 has a gain change of 15% due to temperature. Calculate the change in gain of the feedback amplifier. |
| A. | 0.2% |
| B. | 0.3% |
| C. | 0.4% |
| D. | 0.5% |
| Answer» C. 0.4% | |
| 37. |
Determine the output impedance with feedback for a voltage-series feedback having A = –100, R1 = 15 k, Ro = 20 k, and a feedback of = –0.25. |
| A. | 0.2 k |
| B. | 392.16 |
| C. | 1.82 k |
| D. | 769.23 |
| Answer» E. | |
| 38. |
Determine the input impedance with feedback for a voltage-series feedback having A = –100, R1 = 15 k, Ro = 20 k, and a feedback of = –0.25. |
| A. | 110 k |
| B. | 290 k |
| C. | 390 k |
| D. | 510 k |
| Answer» D. 510 k | |
| 39. |
Determine the voltage gain with feedback for a voltage-series feedback having A = –100, R1 = 15 k, Ro = 20 k, and a feedback of = –0.25. |
| A. | 3.85 |
| B. | –3.85 |
| C. | –9.09 |
| D. | 9.09 |
| Answer» C. –9.09 | |
| 40. |
What is the ratio of the input impedance with series feedback to that without feedback? |
| A. | 1 + A |
| B. | A |
| C. | [C]. |
| D. | 1 |
| Answer» B. A | |
| 41. |
In the astable mode, a 555 timer is connected as a free-running relaxation oscillator. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 42. |
LC feedback elements are normally used in oscillators for frequencies greater than 1 MHz. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 43. |
The feedback network in a Colpitts oscillator contains two series capacitors and a parallel inductor. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 44. |
For a Wien-bridge oscillator, resonance occurs when Vout/Vin = 1. |
| A. | True |
| B. | False |
| Answer» C. | |
| 45. |
The positive feedback voltage in an oscillator has no net phase shift. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 46. |
The frequency in a VCO can be varied with a DC voltage. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 47. |
The start-up gain of an oscillator must be greater than 1. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 48. |
Crystal oscillators are inherently unstable. |
| A. | True |
| B. | False |
| Answer» C. | |
| 49. |
The feedback signal in a Hartley oscillator is derived from an inductive voltage in the tank circuit. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 50. |
Oscillators operate on negative feedback. |
| A. | True |
| B. | False |
| Answer» C. | |