PinoyBIX Engineering Problem Solving and Reference

This is the Multiple Choice Questions in Communications from the book Electronic Devices - Electron Flow Version and Conventional Current Version 8th Edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. In AM, the carrier is changed by a modulating signal. What parameter of the carrier is changed?

• A. amplitude
• B. frequency
• C. pulse width
• D. phase

2. The intermediate frequency in a standard AM receiver is

• A. 455 Hz.
• B. 455 kHz.
• C. 4.55 MHz.
• D. none of the above

3. If a 1 MHz carrier is amplitude modulated with a 5 kHz audio signal, the upper-side frequency is _____ kHz.

• A. 1005
• B. 1000
• C. 995
• D. none of the above

4. For a four-quadrant linear multiplier, what is the output voltage, given input voltages of Vx = +2 V and Vy = –10 V?

• A. +2 V
• B. +1 V
• C. –2 V
• D. –1 V

5. Amplitude modulation is a _____ process.

• A. multiplication
• B. division
• C. sum/difference

6. The output spectrum of a _____ modulator includes upper-side and lower-side frequencies and the carrier frequency.

• A. balanced
• B. standard amplitude
• C. none of the above

7. An AM demodulator can be implemented with a linear multiplier followed by a _____ filter.

• A. low-pass
• B. high-pass
• C. band-pass
• D. band-stop

8. What does VCO stand for?

• A. Visually-Controlled Organization
• B. Voltage-Controlled Oscillator
• C. Voltage-Centered Oscilloscope

9. A phase-locked loop (PLL) is a feedback circuit consisting of a

• A. phase detector.
• B. low-pass filter.
• C. VCO.
• D. all of the above

10. Light may be propagated along a fiber-optic cable in which of the following modes?

• A. multimode step index
• B. single-mode step index
• C. multimode graded index
• D. all of the above

11. In order for a light ray to propagate along a fiber-optic cable, what must the relationship be between the angle of incidence and the critical angle?

• A. θ_i > θ_c
• B. θ_i < θ_c
• C. θ_i = θ_c
• D. none of the above

12. A certain fiber-optic cable has the following characteristics: n₁ = 1.82 and n₂ = 1.73. What is the value of θ_c?

• A. 1.0º
• B. 0.95º
• C. 18.1º
• D. 1.81º

TRUE/FALSE

1. Amplitude modulation is the process of varying the radio frequency with the modulating frequency.

• A. True
• B. False

2. The purpose of the balanced modulator is to remove the carrier frequency.

• A. True
• B. False

3. An AM signal is made up of a carrier, an upper-side frequency, and a lower-side frequency.

• A. True
• B. False

4. The mixer takes the RF signal along with the audio signal to produce the IF signal.

• A. True
• B. False

5. Selectivity in a receiver is provided by the resonant circuits of the IF section.

• A. True
• B. False

6. Frequency modulation is achieved by varying the frequency of an oscillator with a modulating signal.

• A. True
• B. False

7. A VCO is a variable capacitance oscillator.

• A. True
• B. False

8. The demodulator recovers the audio signal from the IF output.

• A. True
• B. False

9. The IF of an FM receiver operates at a center frequency of 455 kHz.

• A. True
• B. False

10. A balanced modulator is used in standard AM to obtain the sum and difference frequencies.

• A. True
• B. False

Check your work.

Complete List of Chapter MCQs in Floyd's Electronic Devices

---

This is the Multiple Choice Questions in Voltage Regulators from the book Electronic Devices - Electron Flow Version and Conventional Current Version 8th Edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. Voltage regulation requires

• A. only line regulation.
• B. only load regulation.
• C. a constant load.
• D. load and line regulation.

2. In Figure 17-1(a)(see question 6), the purpose of R₁ is to

• A. provide a reference voltage.
• B. limit current through the diode.
• C. limit voltage to the op-amp.
• D. provide output voltage sampling.

3. What type of regulator offers inherent short-circuit protection?

• A. shunt regulators
• B. series regulators
• C. three-terminal regulators
• D. switching regulators

4. In a series regulator, what is the purpose of fold-back limiting?

• A. to provide more current in the case of a short circuit
• B. to limit output voltage if input voltage goes too high
• C. to bypass the pass-transistor, if the pass-transistor should fail
• D. to provide current up to a maximum, but drop current to a lower value when the output becomes shorted, to prevent overheating of the device

5. A switching regulator that is configured as a voltage-inverter produces what type of output?

• A. an ac output with opposite phase to the input ac
• B. a dc output that is the negative of the dc input voltage
• C. an output that is a higher voltage than the input voltage
• D. an ac output from a dc input voltage

6. Refer to Figure 17-1(a). Determine the output voltage, V_OUT.

Figure 17-1

• A. 25 V
• B. 5.1 V
• C. 20.2 V
• D. 4.1 V

7. Refer to Figure 17-1(b). If the load is short-circuited, what would be the maximum current through R₁?

• A. 1 A
• B. 1.2 A
• C. 1.5 A
• D. 5 A

8. Refer to Figure 17-1(c). This circuit is called

• A. a series-pass voltage regulator.
• B. a shunt voltage regulator.
• C. a step-up switching regulator.
• D. a step-down switching regulator.

9. Refer to Figure 17-1(b). This circuit is known as

• A. a series-pass voltage regulator.
• B. a shunt voltage regulator.
• C. a step-up switching regulator.
• D. a step-down switching regulator.

10. Refer to Figure 17-1(a). This circuit is known as

• A. a series-pass voltage regulator.
• B. a shunt voltage regulator.
• C. a step-up switching regulator.
• D. a step-down switching regulator.

11. Refer to Figure 17-1(c). This circuit operates at a _____ frequency, and its efficiency is _____.

• A. low, low
• B. low, high
• C. high, high
• D. high, low

12. Refer to Figure 17-1(c). The inductor and capacitor are used for

• A. amplifying the error signal.
• B. controlling the load current.
• C. turning on the pulse-width oscillator.
• D. filtering the dc pulse output.

13. Refer to Figure 17-1(b). The purpose for the zener diode D1 is

• A. to supply a reference voltage.
• B. to amplify the error signal.
• C. to sense the error signal.
• D. to limit the input voltage to the circuit.

14. A voltage regulator has a no-load output of 18 V and a full-load output of 17.3 V. The percent load regulation is

• A. 0.25%.
• B. 96.1%.
• C. 4.05%.
• D. 1.04%.

15. A voltage regulator with a no-load output dc voltage of 12 V is connected to a load with a resistance of 10 Ω. If the load resistance decreases to 7.5 Ω, the load voltage will decrease to 10.9 V. The load current will be _____, and the percent load regulation is _____.

• A. 1.45 A, 90.8%
• B. 1.45 A, 10.09%
• C. 1.2 A, 90.8%
• D. 1.2 A, 10.09%

16. Refer to Figure 17-1(b). If the output of the circuit were to be a short circuit, what power rating would R₁ need to have?

• A. 2.25 W
• B. 5 W
• C. 10 W
• D. 22.5 W

17. Refer to Figure 17-1(a). If the zener diode had a rating of 1.7 V, the output voltage would be

• A. 2.13 V.
• B. 8.36 V.
• C. 20.16 V.
• D. 25 V.

18. Refer to Figure 17-1(a). If the BE junction of Q₁ opens, the output voltage V_OUT will

• A. increase.
• B. decrease.
• C. remain the same.

19. Refer to Figure 17-1(a). If a solder splash shorted the ends of R1 to each other,

• A. the op-amp would fail.
• B. Q₁ would open.
• C. the output voltage would not change.
• D. the zener would fail.

20. Refer to Figure 17-1(c). If the output voltage tends to decrease due to an increase in load current, the transistor will conduct for _____ time each cycle.

• A. a longer
• B. a shorter
• C. the same

21. Voltage regulators keep a constant _____ output voltage when the input or load varies within limits.

• A. dc
• B. ac
• C. ripple

22. _____ regulation can be defined as the percentage change in the output voltage for a given change in the input voltage.

• A. Line
• B. Load

23. _____ regulation can be defined as the percentage change in the output voltage for a given change in load current.

• A. Line
• B. Load

24. In a series linear regulator, the control element is a(n) _____ in series with the load.

• A. inductor
• B. capacitor
• C. transistor

25. In a shunt linear regulator, the control element is a(n) _____ in parallel with the load.

• A. inductor
• B. capacitor
• C. transistor

26. The _____ regulator is less efficient than the _____ type, but offers inherent short-circuit protection.

• A. series, shunt
• B. shunt, series

27. Switching regulators are more efficient than linear regulators and are particularly useful in _____-voltage, _____-current applications.

• A. high, high
• B. low, high
• C. high, low

28. Switching regulator efficiencies can be greater than _____ percent.

• A. 60
• B. 70
• C. 80
• D. 90

29. How many terminals does a 7800 series IC regulator have?

• A. 2
• B. 3
• C. 4
• D. none of the above

TRUE/FALSE

1. A basic voltage regulator consists largely of a reference source, an error detector, and a control device.

• A. True
• B. False

2. Switching regulators are not very efficient.

• A. True
• B. False

3. IC voltage regulators are sometimes called three-terminal regulators.

• A. True
• B. False

4. Load regulation is the percentage change in line voltage for a change in load voltage.

• A. True
• B. False

5. A pass transistor may be used in a series regulator, as the current-carrying device.

• A. True
• B. False

6. Line regulation is the percentage change in output voltage for a given change in input line current.

• A. True
• B. False

7. Under no-load, a shunt regulator has minimum current through the control element.

• A. True
• B. False

8. A switching regulator can be configured as a step-up or a step-down voltage regulator.

• A. True
• B. False

9. For an IC regulator, the input voltage must be at least 2 V above the regulated output voltage.

• A. True
• B. False

10. A three-terminal regulator can be used with an external pass transistor to increase the total load current available.

• A. True
• B. False

Check your work.

Complete List of Chapter MCQs in Floyd's Electronic Devices

---

This is the Multiple Choice Questions in Oscillators from the book Electronic Devices - Electron Flow Version and Conventional Current Version 8th Edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. In order to start up, a feedback oscillator requires

• A. negative feedback less than 1.
• B. positive feedback greater than 1.
• C. unity feedback equal to 1.
• D. no feedback.

2. What is the total phase shift requirement, around the feedback loop, for a phase-shift oscillator?

• A. 90°
• B. 180°
• C. 270°
• D. 360°

3. What is the relationship between the series and parallel resonant frequencies of a quartz crystal?

• A. They are equal.
• B. Parallel resonant frequency is approximately 1 kHz higher than series resonant frequency.
• C. Series resonant frequency is approximately 1 kHz higher than parallel resonant frequency.
• D. none of the above

4. At series resonance, the impedance of a crystal is

• A. minimum.
• B. maximum.
• C. equal.
• D. zero.

5. At parallel resonance, the impedance of a crystal is

• A. minimum.
• B. maximum.
• C. equal.
• D. zero.

6. What is the minimum frequency at which a crystal will oscillate?

• A. seventh harmonic
• B. third harmonic
• C. fundamental
• D. second harmonic

7. Refer to Figure 16-1(a). This circuit is known as

Figure 16-1

• A. a Clapp oscillator.
• B. an Armstrong oscillator.
• C. a Colpitts oscillator.
• D. a Hartley oscillator.

8. Refer to Figure 16-1(b). This circuit is known as

• A. a Clapp oscillator.
• B. an Armstrong oscillator.
• C. a Colpitts oscillator.
• D. a Hartley oscillator.

9. Refer to Figure 16-1(c). This circuit is known as

• A. a Clapp oscillator.
• B. an Armstrong oscillator.
• C. a Colpitts oscillator.
• D. a Hartley oscillator.

10. Refer to Figure 16-1(b). The resonant frequency is controlled by

• A. C₃ and L₁.
• B. C₂, C₄, C5, and L₁.
• C. C₃, C₄, C5, and L₁.
• D. C₃, C₄, C5, and L₂.

11. Calculate the f_r of a lead-lag network if R₁ = R₂ = 6.8 kΩ, and C₁ = C₂ = 0.05 µF.

• A. 468 Hz
• B. 4.68 kHz
• C. 46.8 kHz
• D. 468 kHz

12. Refer to Figure 16-2. Calculate the resonant frequency.

Figure 16-2

• A. 1.126 kHz
• B. 6.17 kHz
• C. 23.9 MHz
• D. 14.1 MHz

13. Refer to Figure 16-3. Determine the resonant frequency.

Figure 16-3

• A. 123.4 kHz
• B. 61.7 kHz
• C. 45.94 kHz
• D. 23.1 kHz

14. Refer to Figure 16-3. If C₁ increases in value, the resonant frequency will

• A. increase.
• B. decrease.
• C. remain the same.
• D. none of the above

15. A certain oscillator has a tap on the inductor in the tank circuit. This oscillator is probably

• A. a Colpitts oscillator.
• B. a Clapp oscillator.
• C. a crystal oscillator.
• D. a Hartley oscillator.

16. An op-amp integrator has a square-wave input. The output should be

• A. a sine wave.
• B. a triangle wave.
• C. a square wave.
• D. pure dc.

17. Refer to Figure 16-4. This circuit is

Figure 16-4

• A. a sine-wave oscillator.
• B. a monostable multivibrator.
• C. an astable multivibrator.
• D. a VCO.

18. Refer to Figure 16-4. Determine the frequency of oscillation, if any.

• A. 131 Hz
• B. 262 Hz
• C. 2.62 kHz
• D. none

19. Refer to Figure 16-4. What is the duty cycle, if any?

• A. 16.3%
• B. 54.5%
• C. 86.9%
• D. none

20. Refer to Figure 16-4. Assuming it is configured as an oscillator and if you desired to reduce the duty to less than 50%, the following circuit change would need to be made.

• A. Reduce the size of R₁.
• B. Reduce the size of R₂.
• C. Increase the size of R₁.
• D. Connect a diode in parallel with R₁.

21. A circuit that can change the frequency of oscillation with an application of a dc voltage is sometimes called

• A. a voltage-controlled oscillator.
• B. a crystal oscillator.
• C. a Hartley oscillator.
• D. an astable multivibrator.

22. Sinusoidal oscillators operate with _____ feedback.

• A. positive
• B. negative

23. One condition for positive feedback is that the phase shift around the feedback loop must be _____°.

• A. 0
• B. 90
• C. 180
• D. 45

24. The start-up gain of an oscillator must be _____ one.

• A. equal to
• B. less than
• C. greater than
• D. none of the above

25. For frequencies up to 1 MHz, the _____ is the most widely used type of sinusoidal RC oscillator.

• A. Wien-bridge
• B. phase-shift
• C. twin-T
• D. none of the above

26. The lead-lag circuit in the Wien-bridge oscillator has a resonant frequency at which the attenuation is

• A. 1/2.
• B. 1/4.
• C. 1/3.
• D. 1/5.

27. The attenuation of the three-section RC feedback phase-shift oscillator is

• A. 1/9.
• B. 1/30.
• C. 1/3.
• D. 1/29.

28. The twin-T oscillator produces a _____ response.

• A. low-pass
• B. high-pass
• C. band-pass
• D. band-stop

29. The feedback signal in a(n) _____ oscillator is derived from a capacitive voltage divider in the LC circuit.

• A. Hartley
• B. Armstrong
• C. Colpitts
• D. none of the above

30. The feedback signal in a(n) _____ oscillator is derived from an inductive voltage divider in the LC circuit.

• A. Hartley
• B. Armstrong
• C. Colpitts
• D. none of the above

TRUE/FALSE

1. Oscillators operate on negative feedback.

• A. True
• B. False

2. The start-up gain of an oscillator must be greater than 1.

• A. True
• B. False

3. The feedback signal in a Hartley oscillator is derived from an inductive voltage in the tank circuit.

• A. True
• B. False

4. Crystal oscillators are inherently unstable.

• A. True
• B. False

5. The frequency in a VCO can be varied with a DC voltage.

• A. True
• B. False

6. LC feedback elements are normally used in oscillators for frequencies greater than 1 MHz.

• A. True
• B. False

7. The positive feedback voltage in an oscillator has no net phase shift.

• A. True
• B. False

8. For a Wien-bridge oscillator, resonance occurs when Vout/Vin = 1.

• A. True
• B. False

9. The feedback network in a Colpitts oscillator contains two series capacitors and a parallel inductor.

• A. True
• B. False

10. In the astable mode, a 555 timer is connected as a free-running relaxation oscillator.

• A. True
• B. False

Check your work.

Complete List of Chapter MCQs in Floyd's Electronic Devices

---

This is the Multiple Choice Questions in Active Filters from the book Electronic Devices - Electron Flow Version and Conventional Current Version 8th Edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. The critical frequency is defined as the point at which the response drops _________ from the passband.

• A. –20 dB
• B. –3 dB
• C. –6 dB
• D. –40 dB

2. Which filter exhibits a linear phase characteristic?

• A. Bessel
• B. Butterworth
• C. Chebyshev
• D. all of the above

3. Which filter has a maximally flat response?

• A. Bessel
• B. Butterworth
• C. Chebyshev
• D. all of the above

4. Which filter exhibits the most rapid roll-off rate?

• A. Bessel
• B. Butterworth
• C. Chebyshev
• D. all of the above

5. A third-order filter will have a roll-off rate of

• A. –20 dB/decade.
• B. –40 dB/decade.
• C. –60 dB/decade.
• D. –30 dB/decade.

6. Refer to Figure 15-1. Identify the frequency response curve for a band-reject filter.

Figure 15-1

• A. a
• B. b
• C. c
• D. d

7. Refer to Figure 15-1. Identify the frequency response curve for a low-pass filter.

• A. a
• B. b
• C. c
• D. d

8. Refer to Figure 15-1. Identify the frequency response curve for a high-pass filter.

• A. a
• B. b
• C. c
• D. d

9. Refer to Figure 15-1. Identify the frequency response curve for a band-pass filter.

• A. a
• B. b
• C. c
• D. d

10. Refer to Figure 15-2(a). This is a _____ filter, and it has a cutoff frequency of _____.

Figure 15-2

• A. high-pass, 21 Hz
• B. low-pass, 21 Hz
• C. high-pass, 2.65 kHz
• D. low-pass, 2.65 kHz

11. Refer to Figure 15-2(b). The cutoff frequency of this filter is _____, and the circuit is known as a _____.

• A. 721 Hz, low-pass filter
• B. 721 Hz, high-pass filter
• C. 72 Hz, low-pass filter
• D. 721 Hz, band-pass filter

12. Refer to Figure 15-2(c). This is a _____ filter.

• A. band-pass
• B. band-stop
• C. high-pass
• D. low-pass

13. Refer to Figure 15-2(d). This circuit is known as a _____ filter, and the fc is _____.

• A. high-pass, 1.59 kHz
• B. band-pass, 15.9 kHz
• C. low-pass, 15.9 kHz
• D. high-pass, 15.9 kHz

14. Refer to Figure 15-2(b). R_A = 2.2 kΩ and R_B = 1.2 kΩ. This filter is probably a

• A. Butterworth type.
• B. Bessel type.
• C. Chebyshev type.
• D. none of the above

15. Refer to Figure 15-2(c). The roll-off of this filter is about

• A. 20 dB/decade.
• B. 40 dB/decade.
• C. 60 dB/decade.
• D. 80 dB/decade.

16. Refer to Figure 15-2(a). The roll-off of the circuit shown is about

• A. 20 dB/decade.
• B. 40 dB/decade.
• C. 60 dB/decade.
• D. 80 dB/decade.

17. A low-pass filter has a cutoff frequency of 1.23 kHz. Determine the bandwidth of the filter.

• A. 2.46 kHz
• B. 1.23 kHz
• C. 644 Hz
• D. not enough information given

18. Refer to Figure 15-3. This is a _____ filter.

Figure 15-3

• A. low-pass
• B. high-pass
• C. band-pass
• D. band-stop

19. Refer to Figure 15-3. This filter has a roll-off rate of

• A. 20 dB/decade.
• B. 40 dB/decade.
• C. 60 dB/decade.
• D. 80 dB/decade.

20. Refer to Figure 15-3. Increasing the values of the filter section resistors in this circuit will cause the f_c to

• A. increase.
• B. decrease.
• C. remain the same.
• D. increase and then decrease.

21. The bandwidth in a _____ filter equals the critical frequency.

• A. low-pass
• B. high-pass
• C. band-pass
• D. band-stop

22. A _____ filter significantly attenuates all frequencies below fc and passes all frequencies above f_c.

• A. low-pass
• B. high-pass
• C. band-pass
• D. band-stop

23. A _____ filter passes all frequencies within a band between a lower and an upper critical frequency and rejects all others outside this band.

• A. low-pass
• B. high-pass
• C. band-pass
• D. band-stop

24. A _____ filter rejects all frequencies within a specified band and passes all those outside this band.

• A. low-pass
• B. high-pass
• C. band-pass
• D. band-stop

25. Filters with the _____ characteristic provide a very flat amplitude in the passband and a roll-off rate of –20 dB/decade/pole.

• A. Butterworth
• B. Chebyshev
• C. Bessel
• D. none of the above

26. Filters with the _____ characteristic are useful when a rapid roll-off is required because it provides a roll-off rate greater than –20/dB/decade/pole.

• A. Butterworth
• B. Chebyshev
• C Bessel
• D. none of the above

27. Filters with the _____ characteristic are used for filtering pulse waveforms.

• A. Butterworth
• B. Chebyshev
• C. Bessel
• D. none of the above

28. The gain of the multiple-feedback band-pass filter above is equal to which of the following? Assume C = C₁ = C₂.

• A. A₀ = R₂ / R₁
• B. A₀ = R₁ / R₂
• C. A₀ = R₂ / 2 R₁
• D. A₀ = R₁ / 2 R₂

29. One important application of a state-variable _____ filter with a summing amplifier is to minimize the 60 Hz "hum" in audio systems.

• A. low-pass
• B. high-pass
• C. band-pass
• D. band-stop

TRUE/FALSE

1. The bandwidth of a band-pass filter is the sum of the two cutoff frequencies.

• A. True
• B. False

2. Butterworth filters have the characteristic of a very flat response in the passband and a roll-off of –20 dB/decade.

• A. True
• B. False

3. Filters with Bessel characteristics are used for filtering pulse waveforms.

• A. True
• B. False

4. In filters, a single RC network is called a pole.

• A. True
• B. False

5. A band-pass filter passes all frequencies within a band between a lower and an upper cutoff frequency.

• A. True
• B. False

6. The bandwidth of a practical high-pass filter is infinite.

• A. True
• B. False

7. A second-order filter has a roll-off of –20 dB/decade.

• A. True
• B. False

8. A Sallen-Key filter is a second-order filter.

• A. True
• B. False

9. An active filter uses capacitors and inductors in the feedback network.

• A. True
• B. False

10. A band-pass filter can be created by cascading a high-pass filter and a low-pass filter.

• A. True
• B. False

Check your work.

Complete List of Chapter MCQs in Floyd's Electronic Devices

---

This is the Multiple Choice Questions in Special-Purpose Op-Amp Circuits from the book Electronic Devices - Electron Flow Version and Conventional Current Version 8th Edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. A log amplifier may use the __________ junction of a BJT in the feedback loop.

• A. base-collector
• B. base-emitter
• C. emitter-collector
• D. emitter-ground

2. An antilog amplifier has a _________ in series with the input.

• A. BJT
• B. diode
• C. diode or BJT
• D. resistor

3. Instrumentation amplifiers are normally used to measure

• A. small differential signal voltages.
• B. signals superimposed on a common-mode voltage often much larger than the signal voltage.
• C. both of the above
• D. none of the above

4. The main difference between the isolation amplifier and an instrumentation amplifier is

• A. an instrumentation amplifier has an input stage.
• B. an instrumentation amplifier has an output stage.
• C. an instrumentation amplifier has a differential stage.
• D. the input, output, and power supply stages of an isolation amplifier are all electrically isolated from each other.

5. An OTA has

• A. a bias-current input terminal.
• B. high output impedance.
• C. no fixed open-loop voltage gain.
• D. all of the above

6. Transconductance is the ratio of the output

• A. current to the input voltage.
• B. current to the input current.
• C. voltage to the input voltage.
• D. voltage to the input current.

7. The log of a number is the

• A. base to which the power must be raised to get that number.
• B. power to which the base must be raised to get that number.
• C. base of that number.
• D. power of that number.

8. What part of the characteristic curve of a diode is useful for log amplifiers?

• A. the log region above 0.7 V
• B. the log region below 0.7 V
• C. the log region between 0 V and 0.7 V
• D. the log region below the zener voltage

9. In logarithmic signal compression,

• A. large and small voltages are compressed equally.
• B. large voltages are compressed more than small voltages.
• C. large voltages are compressed less than smaller voltages.
• D. none of the above

10. A constant-current source delivers a load current that

• A. remains constant when the load resistance changes.
• B. varies with load resistance.
• C. varies inversely with load resistance.
• D. varies inversely with input voltage.

11. A current-to-voltage converter produces a

• A constant output voltage for a variable input current.
• B. variable output voltage for a constant input current.
• C. proportional output voltage for a variable input current.
• D. proportional output current for a variable input voltage.

12. Refer to Figure 14-1(a). This circuit is a setup for

Figure 14-1

• A. an antilog amplifier.
• B. a constant-current source.
• C. an instrumentation amplifier.
• D. an isolation amplifier.

13. Refer to Figure 14-1(b). This circuit is a setup for

• A. an antilog amplifier.
• B. a constant-current source.
• C. an instrumentation amplifier.
• D. an isolation amplifier.

14. Refer to Figure 14-1(c). This circuit is a setup for

• A. an antilog amplifier.
• B. a constant-current source.
• C. an instrumentation amplifier.
• D. an isolation amplifier.

15. Refer to Figure 14-1(d). This circuit is a setup for

• A. an antilog amplifier.
• B. a constant-current source.
• C. an instrumentation amplifier.
• D. an isolation amplifier.

16. The OTA has a _____ input impedance and a _____ CMRR.

• A. high, low
• B. low, high
• C. high, high
• D. low, low

17. Refer to Figure 14-2. Which circuit is known as a voltage-to-current converter?

Figure 14-2

• A. a
• B. b
• C. c
• D. d

18. Refer to Figure 14-2. Which circuit is known as a current-to-voltage converter?

• A. a
• B. b
• C. c
• D. d

19. Refer to Figure 14-2. Which circuit is known as an OTA?

• A. a
• B. b
• C. c
• D. d

20. Refer to Figure 14-2. Which circuit is known as a peak detector?

• A. a
• B. b
• C. c
• D. d

21. A(n) _____ amplifier is a differential voltage-gain device that amplifies the difference between the voltages existing at its two input terminals.

• A. instrumentation
• B. isolation
• C. operational transconductance
• D. log

22. The main purpose of an instrumentation amplifier is to amplify _____ signals that are riding on _____ common-mode voltages.

• A. small, small
• B. small, large
• C. large, small
• D. large, large

23. What is a key characteristic of an instrumentation amplifier?

• A. high CMRR
• B. high output offset
• C. high output impedance
• D. none of the above

24. A basic _____ amplifier is formed by three op-amps and seven resistors.

• A. instrumentation
• B. isolation
• C. log
• D. antilog

25. The voltage gain of a basic instrumentation amplifier is set by a(n)

• A. diode.
• B. capacitor.
• C. resistor.
• D. inductor.

26. A(n) _____ amplifier provides "a barrier" between the input and output for the protection of human life or sensitive equipment.

• A. instrumentation
• B. isolation
• C. operational transconductance
• D. voltage-to-current

27. What is (are) the principal area(s) of application for isolation amplifiers?

• A. medical
• B. power plant
• C. automation
• D. all of the above

28. The operational transconductance amplifier (OTA) is primarily a _____ -to- _____ amplifier.

• A. current, voltage
• B. voltage, current
• C. current, resistance
• D. resistance, current

29. A log amplifier has _____ in the feedback loop.

• A. a diode
• B. a BJT
• C. a resistor
• D. either a diode or a BJT

30. The process known as signal compression is used with a(n) ____ amplifier.

• A. log
• B. antilog
• C. instrumentation
• D. isolation

TRUE/FALSE

1. One of the key characteristics of an instrumentation amplifier is high input impedance.

• A. True
• B. False

2. To construct an instrumentation amplifier, two op-amps and seven resistors are needed.

• A. True
• B. False

3. An isolation amplifier provides ac isolation between input and output.

• A. True
• B. False

4. One of the principal areas of application for an isolation amplifier is power plant instrumentation.

• A. True
• B. False

5. The main purpose of an instrumentation amplifier is to amplify small signals riding on large common-mode voltages.

• A. True
• B. False

6. Instrumentation amplifiers are commonly used in environments with high common-mode noise.

• A. True
• B. False

7. In an isolation amplifier, the third op-amp is used as a unity-gain differential amplifier.

• A. True
• B. False

8. An OTA is primarily a current-to-voltage amplifier.

• A. True
• B. False

9. OTA stands for operational transistor amplifier.

• A. True
• B. False

10. A constant-current source delivers a load current that remains constant only when the load resistance remains constant.

• A. True
• B. False

Check your work.

Complete List of Chapter MCQs in Floyd's Electronic Devices

---

This is the Multiple Choice Questions in Basic Op-Amp Circuits from the book Electronic Devices - Electron Flow Version and Conventional Current Version 8th Edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. If an op-amp comparator has a gain of 100,000, an input difference of 0.2 mV above reference, and a supply of ±12 V, the output will be

• A. 20 V.
• B. 12 V.
• C. 10 V.
• D. 15 V.

2. To reduce the effects of noise resulting in erratic switching of output states of a comparator, you can use

• A. the upper trigger point.
• B. the lower trigger point.
• C. nonzero-level detection.
• D. hysteresis.

3. A comparator with a Schmitt trigger has

• A. two trigger levels.
• B. a fast response.
• C. a slow response.
• D. one trigger level.

4. In a comparator with output bounding, what type of diode is used in the feedback loop?

• A. Schottky
• B. junction
• C. zener
• D. varactor

5. In a flash A/D converter, the priority encoder is used to

• A. select the first input.
• B. select the highest value input.
• C. select the lowest value input.
• D. select the last input.

6. A differentiator is used to measure

• A. the sum of the input voltages.
• B. the difference between two voltages.
• C. the area under a curve.
• D. the rate of change of the input voltage.

7. An op-amp has an open-loop gain of 90,000. V_sat = ±13 V. A differential voltage of 0.1 V p-p is applied between the inputs. What is the output voltage?

• A. 13 V
• B. –13 V
• C. 13 Vp-p
• D. 26 Vp-p

8. Refer to Figure 13-1(a). Determine the output voltage.

Figure 13-1

• A. 1 V
• B. –1 V
• C. +Vsat
• D. –Vsat

9. Refer to Figure 13-1(b). What is the output voltage?

• A. 2 V
• B. –2 V
• C. +Vsat
• D. –Vsat

10. Refer to Figure 13-1(c). With the inputs shown, determine the output voltage.

• A. 7 V
• B. –7 V
• C. +Vsat
• D. –Vsat

11. Refer to Figure 13-2(a). What is the output voltage?

Figure 13-2

• A. 0.5 V
• B. –0.5 V
• C. 2 V
• D. –2 V

12. Refer to Figure 13-2(b). Determine the output voltage, VOUT.

• A. 1.05 V
• B. –0.35 V
• C. 0.35 V
• D. –1.05 V

13. Refer to Figure 13-3(a). Determine the upper trigger point.

Figure 13-3

• A. V(out)max
• B. –V(out)max
• C. –1.41 V
• D. +1.41 V

14. Refer to Figure 13-3(b). Determine the lower trigger point.

• A. +V_(out)max
• B. –V_(out)max
• C. –2.47 V
• D. +2.47 V

15. Refer to Figure 13-4(a). This circuit is known as

Figure 13-4

• A. a noninverting amplifier.
• B. a differentiator.
• C. an integrator.
• D. a summing amplifier.

16. Refer to Figure 13-4(b). This circuit is known as

• A. a noninverting amplifier.
• B. a differentiator.
• C. an integrator.
• D. a summing amplifier.

17. Refer to Figure 13-4(b). A square-wave input is applied to this amplifier. The output voltage is most likely to be

• A. a square wave.
• B. a triangle wave.
• C. a sine wave.
• D. no output.

18. Refer to Figure 13-4(b). If V_in = 5 V, the rate of change of the output voltage in response to a single pulse input is:

• A. 15.2 mV/µs
• B. 1.52 V/µs
• C. 1.52 mV/µs
• D. 15.2 V/µs

19. The output of a Schmitt trigger is a

• A. pulse waveform.
• B. sawtooth waveform.
• C. sinusoidal waveform.
• D. triangle waveform.

20. A Schmitt trigger is

• A. a comparator with only one trigger point.
• B. a comparator with hysteresis.
• C. a comparator with three trigger points.
• D. none of the above.

21. An integrator circuit

• A. uses a resistor in its feedback circuit.
• B. uses an inductor in its feedback circuit.
• C. uses a capacitor in its feedback circuit.
• D. uses a resistor in its feedback circuit or uses a capacitor in its feedback circuit

22. In a(n) _____, when the input voltage exceeds a specified reference voltage, the output changes state.

• A. integrator
• B. differentiator
• C. summing amplifier
• D. comparator

23. A good example of hysteresis is a(n)

• A. AM radio.
• B. thermostat.
• C. alarm clock.
• D. none of the above

24. A comparator with hysteresis is sometimes known as a(n)

• A. integrator.
• B. differentiator.
• C. Schmitt trigger.
• D. none of the above

25. What is (are) the necessary component(s) for the design of a bounded comparator?

• A. rectifier diodes
• B. zener diodes
• C. both of the above

26. Which of the following are variations of the basic summing amplifier?

• A. averaging amplifier
• B. scaling amplifier
• C. both of the above

27. What circuit produces an output that approximates the area under the curve of an input function?

• A. integrator
• B. differentiator
• C. summing amplifier
• D. comparator

28. _____ is a mathematical process for determining the rate of change of a function.

• A. Integration
• B. Differentiation
• C. Summing
• D. Comparatoring

29. A(n) ______ amplifier is a summing amplifier with a closed-loop gain equal to the reciprocal of the number of inputs.

• A. averaging
• B. scaling
• C. differentiating
• D. none of the above

30. What type(s) of circuit(s) use comparators?

• A. summer
• B. nonzero-level detector
• C. averaging amplifier
• D. summer and nonzero-level detector

TRUE/FALSE

1. In an op-amp comparator, when the input voltage exceeds a reference voltage, the voltage output changes state.

• A. True
• B. False

2. Bounding allows the output of a comparator to be an unlimited voltage.

• A. True
• B. False

3. A positive feedback network for hysteresis improves an op-amp comparator's noise immunity.

• A. True
• B. False

4. Operational amplifiers are never used as nonlinear devices.

• A. True
• B. False

5. The output voltage of a summing amplifier is proportional to the sum of the input voltages.

• A. True
• B. False

6. The difference between the UTP and the LTP is the hysteresis voltage.

• A. True
• B. False

7. An op-amp integrator uses a capacitor as the feedback element.

• A. True
• B. False

8. An op-amp can be used as a comparator to determine when an input voltage exceeds a certain level.

• A. True
• B. False

9. The output of an op-amp comparator will be zero when the input voltage exceeds the reference voltage.

• A. True
• B. False

10. The R/2R ladder is commonly used for D/A converters.

• A. True
• B. False

Check your work.

Complete List of Chapter MCQs in Floyd's Electronic Devices

---

This is the Multiple Choice Questions in The Operational Amplifier from the book Electronic Devices - Electron Flow Version and Conventional Current Version 8th Edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. Refer to Figure 12-1(a). This amplifier is known as

Figure 12-1

• A. an inverting amplifier.
• B. a non-inverting amplifier.
• C. a voltage-follower.
• D. a common-source amplifier.

2. Refer to Figure 12-1(b). This amplifier is known as

• A. an inverting amplifier.
• B. a non-inverting amplifier.
• C. a voltage-follower.
• D. a common-source amplifier.

3. Refer to Figure 12-1(c). This amplifier is known as

• A. an inverting amplifier.
• B. a non-inverting amplifier.
• C. a voltage-follower.
• D. a common-source amplifier.

4. Refer to Figure 12-1(a). A dc voltage of –1.2 V is applied. V_CC = ±12 V. What is the output voltage?

• A. 1.2 V
• B. –1.2 V
• C. 0 V
• D. 12 V

5. Refer to Figure 12-1(b). The voltage gain of this amplifier is

• A. 100.
• B. 5.
• C. 20.
• D. 21.

6. Refer to Figure 12-1(c). If an input signal of –0.5 V were applied, determine the output voltage.

• A. –5 V
• B. 5 V
• C. 10 V
• D. –10 V

7. Refer to Figure 12-1(c). The input impedance of this circuit is

• A. 500 kΩ.
• B. 10 kΩ.
• C. 50 kΩ.
• D. 5 kΩ.

8. Refer to Figure 12-1(c). You need an amplifier with an input impedance of 12 kΩ. You must not change the amplifier voltage gain. The new value of R_i would be _____ and the new value of R_f would be _____.

• A. 10 kΩ, 100 kΩ
• B. 13.3 kΩ, 120 kΩ
• C. 12 kΩ, 108 kΩ
• D. 12 kΩ, 120 kΩ

9. Refer to Figure 12-1(b). A dc input signal of –50 mV is applied. You would measure _____ from the inverting input to ground.

`

• A. 50 mV
• B. 1.05 V
• C. –1.05 V
• D. –50 mV

10. It takes an op-amp 22 µs to change its output from –15 V to +15 V. Determine the slew rate.

• A. 1.36 V/µs
• B. 0.68 V/µs
• C. –0.68 V/µs
• D. cannot determine

11. Refer to Figure 12-2. The purpose of R₁ and R₂ is

Figure 12-2

• A. for bias current compensation.
• B. for input offset voltage compensation.
• C. to set input impedance.
• D. to set input impedance and voltage gain.

12. Refer to Figure 12-2. The purpose of R₄ is

• A. for bias current compensation.
• B. for input offset voltage compensation.
• C. to set input impedance.
• D. to set input impedance and voltage gain.

13. Refer to Figure 12-2. The purpose of R₃ is

• A. for bias current compensation.
• B. for input offset voltage compensation.
• C. to set input impedance.
• D. to set input impedance and voltage gain.

14. Refer to Figure 12-2. If the value of R₁ decreases, the voltage gain will _____ and the input impedance will _____.

• A. increase, increase
• B. increase, decrease
• C. decrease, decrease
• D. decrease, increase

15. A voltage-follower amplifier comes to you for service. You find the voltage gain to be 5.5 and the input impedance 22 kΩ. The probable fault in this amplifier, if any, is

• A. the gain is too low for this type of amplifier.
• B. the input impedance is too high for this amplifier.
• C. nothing is wrong. The trouble must be somewhere else.
• D. none of these.

16. 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

17. 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.

18. An RC network has R = 47 kΩ and C = 0.22 µF. What is the cutoff frequency?

• A. 154 Hz
• B. 1540 Hz
• C. 1.54 Hz
• D. 15.4 Hz

19. An RC network has R = 500 kΩ 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

20. 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

21. 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.

22. Refer to Figure 12-3(a). Find the midrange gain of this amplifier.

Figure 12-3

• A. 26.7
• B. –26.7
• C. 27.7
• D. –27.7

23. Refer to Figure 12-3(b). Find the midrange gain of this op-amp amplifier.

• A. 10
• B. 11
• C. –10
• D. –11

24. Refer to Figure 12-3(c). The midrange voltage gain of this amplifier is

• A. 0.5.
• B. 27.7.
• C. –11.
• D. 1.

25. Refer to Figure 12-3(a). The op-amp has a unity-gain bandwidth of 3 MHz. Determine the BW of the circuit.

• A. 3 MHz
• B. 30 kHz
• C. 112.4 kHz
• D. infinite in width

26. Refer to Figure 12-3(b). The op-amp has a unity-gain bandwidth of 1.7 MHz. Find the bandwidth of the circuit.

• A. 155 MHz
• B. 155 kHz
• C. 155 Hz
• D. 15.5 Hz

27. Refer to Figure 12-3(c). The unity-gain bandwidth of this op-amp is 10.4 kHz. What is the bandwidth of the circuit?

• A. 10.4 kHz
• B. 15.5 kHz
• C. 3 MHz
• D. 16.7 kHz

28. Refer to Figure 12-4(a). Determine the bandwidth.

Figure 12-4

• A. 1 MHz
• B. 1.5 MHz
• C. 1 kHz
• D. 1.5 kHz

29. Refer to Figure 12-4(b). Calculate the bandwidth.

• A. 8.33 MHz
• B. 833 kHz
• C. 83.3 kHz
• D. 8.33 kHz

30. Negative feedback added to an op-amp _____ the bandwidth and _____ the gain.

• A. increases, increases
• B. increases, decreases
• C. decreases, decreases
• D. decreases, increases

31. 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

32. 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

33. 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

34. 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. none of the above

35. A(n) _____ amplifier configuration has an input impedance approximately equal to the input resistor Ri and an output impedance approximately equal to the output impedance of the op-amp itself.

• A. non-inverting
• B. inverting
• C. voltage-follower
• D. none of the above

36. 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. none of the above

37. Open-loop voltage gain of an op-amp can range up to _____.

• A. 10,000
• B. 50,000
• C. 100,000
• D. 200,000

38. The ______ is the voltage gain of an op-amp with external feedback.

• A. A_ol
• B. A_cl
• C. A_v
• D. none of the above

39. A three-stage op-amp can have a maximum phase lag of _____°.

• A. –180
• B. –90
• C. –270
• D. none of the above

TRUE/FALSE

1. A good op-amp has low voltage gain, low output impedance, and high input impedance.

• A. True
• B. False

2. The common-mode rejection ratio (CMRR) is a measure of an op-amp's ability to reject common-mode input signals.

• A. True
• B. False

3. An inverting amplifier has an input impedance equal to the feedback resistor R_f.

• A. True
• B. False

4. A non-inverting amplifier has a higher input impedance and a lower output impedance than the op-amp itself (without feedback).

• A. True
• B. False

5. All practical op-amps have input bias currents and voltages that produce output error voltages.

• A. True
• B. False

6. Open-loop gain of an op-amp is the voltage gain without feedback.

• A. True
• B. False

7. Closed-loop gain is the gain with negative feedback.

• A. True
• B. False

8. Open-loop gain is always smaller than closed-loop gain.

• A. True
• B. False

9. Negative feedback decreases the bandwidth and increases the voltage gain.

• A. True
• B. False

10. When the open-loop gain of an op-amp is reduced by negative feedback, the bandwidth is increased.

• A. True
• B. False

Check your work.

Complete List of Chapter MCQs in Floyd's Electronic Devices

---

This is the Multiple Choice Questions in Thyristors from the book Electronic Devices - Electron Flow Version and Conventional Current Version 8th Edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. Refer to Figure 11-1. Identify the triac.

Figure 11-1

• A a
• B. b
• C. c
• D. d
• E. e

2. Refer to Figure 11-1. Which symbol represents a UJT?

• A a
• B. b
• C. c
• D. d
• E. e

3. Refer to Figure 11-1. Identify the symbol for an SCS.

• A a
• B. b
• C. c
• D. d
• E. e

4. Refer to Figure 11-1. Identify the diac symbol.

• A a
• B. b
• C. c
• D. d
• E. e

5. Refer to Figure 11-1. What is the correct symbol for an SCR?

• A. a
• B. b
• C. c
• D. d
• E. e

6. You have a need to use a device to trigger an SCR. A good one to use might be

• A. an SCS.
• B. a UJT.
• C. a 4-layer diode.
• D. a PUT.

7. Which of the following devices might best be used to control an electric motor?

• A. an SCS
• B. a PUT
• C. an SCR
• D. a diac

8. An SCR acts to control the speed of an electric motor by _____ the _____ of the pulse delivered to the motor.

• A. varying, width
• B. increasing, amplitude
• C. decreasing, gate width
• D. none of these

9. You need to design a relaxation oscillator circuit. The most likely device to use might be

• A. an SCR.
• B. a UJT.
• C. a triac.
• D. a 4-layer diode.

10. You need a very efficient thyristor to control the speed of an AC fan motor. A good device to use would be

• A. a 4-layer diode.
• B. a PUT.
• C. a triac.
• D. a BJT.

11. You have the schematic diagram of several types of circuits. Which of these circuits most likely uses a triac?

• A. an oscillator
• B. an ac motor control
• C. a programmable oscillator
• D. an amplifier

12. You have a light-dimmer circuit using an SCR. In testing the circuit, you find that I_G = 0 mA and the light is still on. You conclude that the trouble might be one of the following:

• A. the SCR is open.
• B. the switch is faulty.
• C. the gate circuit is shorted.
• D. this is normal; nothing is wrong.

13. Your boss has asked you to recommend a thyristor that will enable you to turn it on with a pulse and also turn it off with a pulse. Which of the following should you recommend?

• A. an SCR
• B. an SCS
• C. a PUT
• D. a triac

14. How many semiconductor layers are thyristors constructed with?

• A. 2
• B. 3
• C. 4
• D. 5

15. The SCR can be triggered on by a pulse at the

• A. gate.
• B. anode.
• C. cathode.
• D. none of the above

16. An application of a(n) _____ is in a lighting system for power interruptions.

• A. SCR
• B. SCS
• C. diac
• D. triac

17. The _____ can conduct current in either direction and is turned on when a breakover voltage is exceeded.

• A. SCR
• B. diac
• C. SCS
• D. triac

18. The _____ is like a diac with a gate terminal.

• A. triac
• B. SCR
• C. SCS
• D. none of the above

19. The silicon-controlled switch (SCS) is similar in construction to the

• A. triac.
• B. diac.
• C. SCR.
• D. 4-layer diode.

20. The ______ can be externally programmed to turn on at a desired anode-to-gate voltage level.

• A. UJT
• B. PUT
• C. SCR
• D. SCS

21. Identify the symbol:

• A. SCS
• B. PUT
• C. LASCR
• D. diac

22. Identify the symbol:

• A. triac
• B. PUT
• C. LASCR
• D. SCR

TRUE/FALSE

1. Thyristors are 4-layer semiconductor devices.

• A. True
• B. False

2. The SCR is a device that can be triggered off by a pulse applied to the gate.

• A. True
• B. False

3. The diac can conduct current in either direction and is turned on when a breakover voltage is exceeded.

• A. True
• B. False

4. The anode-to-gate voltage can be used to turn the PUT on or off.

• A. True
• B. False

5. The triac can be turned on or off by a pulse at the gate.

• A. True
• B. False

6. The SUS is also known as a Shockley diode.

• A. True
• B. False

7. The SCS is turned on with the cathode gate, and turned off with the anode gate.

• A. True
• B. False

8. In an SCR-based half-wave phase-control circuit, a diode is connected in series with the anode.

• A. True
• B. False

9. UJTs can only be used to trigger triacs, not SCRs.

• A. True
• B. False

10. The triac is similar to an SCR, but it provides conduction for both halves of the ac wave.

• A. True
• B. False

Check your work.

Complete List of Chapter MCQs in Floyd's Electronic Devices

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