Online Questions and Answers Topic Outline
- MCQs in Logarithms
- MCQs in Decibels
- MCQs in General Frequency Considerations
- MCQs in Low-frequency analysis - Bode Plot
- MCQs in Low-frequency response - BJT Amplifier
- MCQs in Low-frequency response - FET Amplifier
- MCQs in Miller Effect Capacitance
- MCQs in High-frequency response - BJT Amplifier
- MCQs in High-frequency response - FET Amplifier
- MCQs in Multistage Frequency Effects
- MCQs in Square wave testing
- MCQs in Computer Analysis
Practice Exam Test Questions
Choose the letter of the best answer in each questions.
1. What is the ratio of the common logarithm of a number to its natural logarithm?
- a. 0.435
- b. 2
- c. 2.3
- d. 3.2
2. logea = _____ log10a
- a. 2.3
- b. 2.718
- c. e
- d. 1.414
3. By what factor does an audio level change if the power level changes from 4 W to 4096 W?
- a. 2
- b. 4
- c. 6
- d. 8
4. The input power to a device is 10,000 W at 1000 V. The output power is 500 W, and the output impedance is 100 Ω. Find the voltage gain in decibels.
- a. –30.01 dB
- b. –20.0 dB
- c. –13.01 dB
- d. –3.01 dB
5. What magnitude voltage gain corresponds to a decibel gain of 50?
- a. 31.6238
- b. 316.228
- c. 3162.38
- d. 31623.8
6. An amplifier rated at 30-W output is connected to a 5-Ω speaker. Calculate the input power required for full power output if the power gain is 20 dB.
- a. 3 mW
- b. 30 mW
- c. 300 mW
- d. 3 W
7. An amplifier rated at 30-W output is connected to a 5-Ω speaker. Calculate the input voltage for the rated output if the amplifier voltage gain is 20 dB.
- a. 1.225 mV
- b. 12.25 mV
- c. 122.5 mV
- d. 1.225 V
8. For audio systems, the reference level is generally accepted as
- a. 1 mW
- b. 1 W
- c. 10 mW
- d. 100 mW
9. For which of the following frequency region(s) can the coupling and bypass capacitors no longer be replaced by the short-circuit approximation?
- a. Low-frequency
- b. Mid-frequency
- c. High-frequency
- d. All of the above
10. By what other name(s) are the cut-off frequencies in a frequency response plot called?
- a. Corner frequency
- b. Break frequency
- c. Half-power frequency
- d. All of the above
11. What is the ratio of the output power to the input power at the cut-off frequencies in a normalized frequency response plot?
- a. 0.25
- b. 0.50
- c. 0.707
- d. 1
12. What is the ratio of the output voltage to the input voltage at the cut-off frequencies in a normalized frequency response plot?
- a. 0.25
- b. 0.50
- c. 0.707
- d. 1
13. What is the normalized gain expressed in dB for the cut-off frequencies?
- a. –3 dB
- b. +3 dB
- c. –6 dB
- d. –20 dB
14. The ________-frequency response of a transformer-coupled system is calculated primarily by the stray capacitance between the turns of the primary and secondary windings.
- a. Low
- b. Mid
- c. High
15. The larger capacitive elements of the design will determine the ________ cut-off frequency.
- a. Low
- b. Mid
- c. High
16. The smaller capacitive elements of the design will determine the ________ cut-off frequencies.
- a. Low
- b. Mid
- c. High
17. What is the ratio of the capacitive reactance XCS to the input resistance RI of the input RC circuit of a single-stage BJT amplifier at the low-frequency cut-off?
- a. 0.25
- b. 0.50
- c. 0.75
- d. 1.0
18. In the input RC circuit of a single-stage BJT, by how much does the base voltage lead the input voltage for frequencies much larger than the cut-off frequency in the low-frequency region?
- a. About 0º
- b. 45º
- c. About 90º
- d. None of the above
19. In the input RC circuit of a single-stage BJT, by how much does the base voltage lead the input voltage at the cut-off frequency in the low-frequency region?
- a. About 0º
- b. 45º
- c. About 90º
- d. None of the above
20. Determine the break frequency for this circuit.
- a. 15.915 Hz
- b. 159.15 Hz
- c. 31.85 Hz
- d. 318.5 Hz
21. Refer to Figure 9.19. Calculate θ at 0.5f1.
- a. 63.43º
- b. 26.56º
- c. 45º
- d. Undefined
22. A change in frequency by a factor of ________ is equivalent to 1 octave.
- a. 2
- b. 10
- c. 5
- d. 20
23. A change in frequency by a factor of ________ is equivalent to 1 decade.
- a. 2
- b. 10
- c. 5
- d. 20
24. For the low-frequency response of a BJT amplifier, the maximum gain is where ________ .
- a. RB = 0 Ω
- b. RC = 0 Ω
- c. RE = 0 Ω
25. Which of the low-frequency cutoffs determined by CS, CC, or CE will be the predominant factor in determining the low-frequency response for the complete system?
- a. Lowest
- b. Middle
- c. Highest
- d. None of the above
26. Determine the lower cut-off frequency of this network.
- a. 15.8 Hz
- b. 46.13 Hz
- c. 238.73 Hz
- d. 1575.8 Hz
27. Which of the following elements is (are) important in determining the gain of the system in the high-frequency region?
- a. Interelectrode capacitances
- b. Wiring capacitances
- c. Miller effect capacitance
- d. All of the above
28. In the ________-frequency region, the capacitive elements of importance are the interelectrode (between terminals) capacitances internal to the active device and the wiring capacitance between the leads of the network.
- a. Low
- b. Mid
- c. High
29. Which of the following capacitors is (are) included in Ci for the high-frequency region of a BJT or FET amplifier?
- a. Input wiring capacitance
- b. The transition capacitance (
)
- c. Miller capacitance
- d. All of the above
30. In the hybrid 
- a. Base spreading resistance
- b. Base contact
- c. Base bulk
- d. All of the above
31. Which of the following configurations does (do) not involve the Miller effect capacitance?
- a. Common-emitter
- b. Common-base
- c. Common-collector
- d. All of the above
32. A 3-dB drop in hfe will occur at a frequency defined by ________.
- a.
- b.
- c. 1
- d. 2
33. What is the range of the capacitors Cgs and Cgd?
- a. 1 to 10 pF
- b. 1 to 10 nF
- c. 1 to 10 F
- d. 1 to 10 F
34. What is the range of the capacitor Cds?
- a. 0.01 to 0.1 pF
- b. 0.1 to 1 pF
- c. 0.1 to 1 nF
- d. 0.1 to 1 F
35. Which of the following statements is true for a square-wave signal?
- a. It is composed of both even and odd harmonics.
- b. It is composed only of odd harmonics.
- c. It is composed only of even harmonics.
- d. The harmonics waveforms are also square waves.
FILL-IN-THE-BLANKS
1. Logarithms taken to the base _____ are referred to as common logarithms, while logarithms taken to the base _____ are referred to as natural logarithms.
- A. 10, e
- B e, 10
- C. 5, e
- D. 10, 5
2. The logarithm of a number _____ than 1 is always _____.
- A. greater, negative
- B. less, positive
- C. less, negative
- D. None of the above
3. The decibel (dB) is defined such that _____ decibel(s) = _____ bel(s).
- A. 1, 10
- B. 10, 1
- C. 1, 1
- D. 10, 10
4. The resistance associated with the 1-mW power level is _____ , chosen because it is the characteristic impedance of audio transmission lines.
- A. 100
- B. 250
- C. 400
- D. 600
5. The decibel gain of a cascaded system is the _____ of the decibel gains of each stage.
- A. sum
- B. difference
- C. product
- D. quotient
6. Voltage gains of _____ dB or higher should immediately be recognized as being quite high.
- A. 3
- B. 6
- C. 20
- D. 50
7. For the RC-coupled amplifier, the drop in gain at low frequencies is due to the increasing reactance of _____.
- A. CC
- B. Cs
- C. CE
- D. All of the above
8. To fix the frequency boundaries of relatively high gain, _____ was chosen to be the gain at the cut-off levels.
- A. 0.5Av mid
- B. 0.707Av mid
- C. Av low
- D. 0.5Av high
9. In the input RC circuit of a single-stage BJT or FET amplifier, as the frequency _____, the capacitive reactance _____ and _____ of the input voltage appears across the output terminals.
- A. increases, decreases, more
- B. increases, decreases, less
- C. increases, increases, more
- D. decreases, decreases, less
10. A change in frequency by a factor of 2 results in a _____ change in the ratio of the normalized gain.
- A. 3-dB
- B. 6-dB
- C. 10-dB
- D. 20-dB
11. A change in frequency by a factor of 10 results in a _____ change in the ratio of the normalized gain.
- A. 3-dB
- B. 6-dB
- C. 10-dB
- D. 20-dB
12. In the low-frequency region, the _____ low-frequency cut-off determined by CS, CC, or CE will have the greatest impact on the network.
- A. highest
- B. average
- C. lowest
- D. None of the above
13. The _____ region produces the maximum voltage gain in a single-stage BJT or FET amplifier.
- A. low-frequency
- B. mid-frequency
- C. high-frequency
- D. None of the above
14. For any inverting amplifier, the impedance capacitance will be _____ by a Miller effect capacitance sensitive to the gain of the amplifier and the interelectrode capacitance.
- A. unaffected
- B. increased
- C. decreased
- D. None of the above
15. The Miller effect is meaningful in the _____ amplifier.
- A. inverting
- B. noninverting
- C. inverting/noninverting
- D. None of the above
16. With a BJT amplifier in the high-frequency region, the capacitance Cbe is the _____ of the parasitic capacitances while Cce is the _____.
- A. smallest, largest
- B. largest, smallest
- C. smallest, medium
- D. None of the above
17. At very high frequencies, the effect of Ci is to _____ the total impedance of the parallel combination of R1, R2, R3, and Ci.
- A. increase
- B. maintain
- C. decrease
- D. None of the above
18. If the parasitic capacitors were the only elements to determine the high cut-off frequency, the _____ frequency would be the determining factor.
- A. lowest
- B. highest
- C. lowest or highest
- D. None of the above
19. The _____ configuration displays improved high-frequency characteristics over the _____ configuration.
- A. common-collector, common-emitter
- B. common-emitter, common-base
- C. common-emitter, common-collector
- D. common-base, common-emitter
20. The _____ of the upper cut-off frequencies defines a _____ possible bandwidth for a system.
- A. highest, maximum
- B. lowest, maximum
- C. lowest, minimum
- D. None of the above
21. 
- A. significantly smaller
- B. smaller
- C. significantly greater
- D. None of the above
22. For two identical stages in cascade, the drop-off rate in the high- and low-frequency regions has increased to _____ per decade.
- A. –3 dB
- B. –6 dB
- C. –20 dB
- D. –40 dB
23. The bandwidth _____ in a multistage amplifier compared to an identical single-stage amplifier.
- A. increases
- B. decreases
- C. remains the same
- D. None of the above
24. The _____ in the Fourier series has the same frequency as the square wave itself.
- A. fundamental
- B. third harmonic
- C. fifth harmonic
- D. seventh harmonic
25. The magnitude of the third harmonic is _____ of the magnitude of the fundamental.
- A. 1
- B. 0.5
- C. 0.33
- D. 0.25
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