Source text. Published from the recorded source PDF for NEETS Module 9: Wave Generation and Wave Shaping.
INDEX-1
Module 9 Index
A Amplitude stability, 2-13 Armstrong oscillator, 2-13 to 2-17 B Bandwidth, 1-27 to 1-29 Basic oscillator, the, 2-2, 2-3 Blocking oscillators, 3-24 to 3-30 C Circuits, oscillator, 2-11 to 2-30 Clampers, 4-16 to 4-28 Classification of oscillators (generators), 2-1, 2-2 Colpitts oscillator, 2-19 to 2-21 Common-base transistor damper, 4-28, 4-29 Composition of nonsinusoidal waves, 4-30 to 4-35 Configuration of oscillators, 2-9 to 2-11 common-base configuration, 2-10 common-collector configuration, 2-10 common-emitter configuration, 2-10, 2-11 Counters, 4-46 to 4-52 Crystal oscillators, 2-24 to 2-28 D Differentiators, 4-42 to 4-46 Dual-diode limiter, 4-15, 4-16 F Feedback, 2-8, 2-9 Filters, 1-29 to 1-40 Filter circuits, resonant circuits as, 1-35 to 1-38 Frequency effects on RLC circuits, 1-3 to 1-5 Frequency multiplication, 2-31 to 2-32 Frequency, resonant, 1-6 to 1-8 Frequency stability, 2-12, 2-13 G Generator, waveform, 3-5 to 3-48 Glossary, AI-I to AI-4 H Harmonics, 2-30 to 2-33 Hartley oscillator, 2-17 to 2-19 High-pass filter, 1-33, 1-35 I Integrator waveform analysis, 4-38 to 4-42 L Learning objectives, 1-1, 2-1, 3-1, 4-1 generators, 3-1 oscillators, 2-1 tuned circuits, 1-1 wave shaping, 4-1 waveforms and wave Limiters, 4-1 to 4-15 Low-pass filter, 1-32, 1-33 M Multisection filters, 1-38 to 1-40 Multivibrators, 3-5 to 3-23 N Negative diode dampers, 4-24 to 4-28 O Oscillators, 2-1 to 2-33 configuration of oscillators, 2-9 to 2-11 common-base configuration, 2-10 common-collector configuration, 2-10 common-emitter configuration, 2-10, 2-11 feedback, 2-8, 2-9 types of feedback, 2-9 harmonics, 2-30 to 2-33 frequency multiplication, 2-31, 2-32 introduction, 2-1 to 2-11 basic oscillator, the, 2-2, 2-3 INDEX-2 Oscillators—Continued classification of oscillators (generators), 2-1, 2-2 sine-wave oscillator, 2-3 to 2-6 solid-state LC oscillators, 2-8 oscillator circuits, 2-11 to 2-30 amplitude stability, 2-13 Armstrong oscillator, 2-13 to 2-17 Colpitts oscillator, 2-19 to 2-21 crystal oscillators, 2-24 to 2-28 frequency stability, 2-12, 2-13 Hartley oscillator, 2-17 to 2-19 pulsed oscillators, 2-28 to 2-30 resistive-capacitive (RC) feedback oscillator, 2-21 to 2-24 summary, 2-33 to 2-37 P Parallel limiters, 4-9 to 4-15 Parallel resonance, 1-18 to 1-20 Periodic waveforms, 3-1 to 3-5 Positive-diode dampers, 4-19 to 4-24 Pulsed oscillators, 2-28 to 2-30 R RC integrators, 4-35 to 4-38 Resonance, 1-5, 1-6 Resonant circuits, 1-8 to 1-18 Resonant circuits as filters, 1-35 to 1-38 Resonant frequency, 1-6 to 1-8 Resistive-capacitive (RC) feedback oscillator, 2-21 to 2-24 RL integrators, 4-38 RLC circuits, frequency effects on, 1-3 to 1-5 S Series limiters, 4-1 to 4-9 Series RC circuits, 4-18, 4-19 Series/parallel a.c. circuits, review of, 1-3 to 1-5 Series-resonant circuit, the ideal, 1-9 to 1-18 Shaping circuits, 4-19 to 4-35 Sine-wave oscillator, 2-3 to 2-6 Solid-state LC oscillators, 2-8 Square and square roots, AII-1 T Time-base generators, 3-31 to 3-48 Tuned circuits, 1-1 to 1-41 bandwidth, 1-27 to 1-29 filters, 1-29 to 1-40 high-pass filter, 1-33 to 1-35 low-pass filter, 1-32 to 1-33 multisection filters, 1-38 to 1-40 resonant circuits as filters, 1-35 to 1-38 introduction to tuned circuits, 1-1 to 1-26 resonance, 1-5, 1-6 resonant frequency, 1-6 to 1-8 resonant circuits, 1-8 to 1-18 ideal series-resonant circuit, the, 1-9 to 1-18 parallel resonance, 1-18 to 1-20 resonant circuits as filter circuits, 1-21 to 1-26 idea of “Q”, the, 1-21 to 1-26 review of series/parallel a.c. circuits, 1-3 to 1-5 frequency effects on RLC circuits, 1-3 to 1-5 safety precautions, 1-40, 1-41 summary, 1-41 to 1-48 Types of feedback, 2-9 W Wave shaping, 4-1 to 4-52 clampers, 4-16 to 4-29 common-base transistor damper, 4-28, 4-29 negative-diode dampers, 4-24 to 4-28 positive-diode dampers, 4-19 to 4-24 series RC circuits, 4-18, 4-19 limiters, 4-1 to 4-15 dual-diode limiter, 4-15, 4-16 parallel limiters, 4-9 to 4-15 series limiters, 4-1 to 4-9 shaping circuits, 4-30 to 4-52 composition of nonsinusoidal waves, 4-30 to 4-35 INDEX-3 Wave shaping—Continued counters, 4-46 to 4-52 differentiators, 4-42 to 4-46 integrator waveform analysis, 4-38 to 4-42 RC integrators, 4-35 to 4-38 RL integrators, 4-38 summary, 4-52 to 4-59 Waveforms and wave generators, 3-1 to 3-48 summary, 3-48 to 3-53 waveform generator, 3-5 to 3-48 blocking oscillator, 3-24 to 3-30 multivibrators, 3-5 to 3-23 time-base generators, 3-31 to 3-48 waveforms, 3-1 to 3-5 periodic waveforms, 3-1 to 3-5 Assignment Questions Information: The text pages that you are to study are provided at the beginning of the assignment questions.
1
Assignment 1
Textbook assignment: Chapter 1, “Tuned Circuits,” pages 1-1 through 1-52. _________________________________________________________________________________ 1-1. An inductor presents which of the following types of electrical opposition to ac current flow? 1. Reactance 2. Resistance 3. Inductance 4. Capacitance 1-2. Which of the following electrical characteristics determines the magnitude of inductive reactance? 1. Resistance 2. Frequency only 3. Inductance only 4. Frequency and inductance 1-3. Which of the following values represents an inductive reactance?
1. X C = 2,220 ohms 2. X L = 220 ohms 3. L = 22 millihenries 4. C = 22 microfarads 1-4. What formula is used to calculate inductive reactance? 1. 3. 2. 4. 1-5. In an ac circuit, how does inductive reactance respond to an increase in applied frequency? 1. Inductive reactance increases 2. Inductive reactance decreases 3. Inductive reactance remains the same 1-6. What term describes the opposition to ac that causes current to lead voltage? 1. Resistance 2. Conductance 3. Inductive reactance 4. Capacitive reactance 1-7. In an ac circuit, how does capacitive reactance respond to an increase in applied frequency?
1. Capacitive reactance increases 2. Capacitive reactance decreases 3. Capacitive reactance remains the same 1-8. In an ac circuit, what is the term that describes the TOTAL opposition to current flow? 1. Impedance 2. Inductance 3. Resistance 4. Capacitance 1-9. In an ac circuit that contains an inductive reactance of 7,250 ohms and a capacitive reactance of 9,775 ohms, what is the resultant reactance? 1. - 2,525 ohms 2. -10,250 ohms 3. 2,525 ohms 4. 10,250 ohms 1-10. When an ac circuit is at resonance, what is the relationship between XL and XC 1. X L is equal to XC 2. X L is less than XC 3. X L is greater than XC 2 1-11. What formula is used to calculate resonant frequency?
1. 3. 2. 4. 1-12. In a tank circuit, how does the resonant frequency of the circuit respond to an increase in (a) capacitance and (b) inductance? 1. (a) Increases (b) increases 2. (a) Increases (b) decreases 3. (a) Decreases (b) decreases 4. (a) Decreases (b) increases 1-13. In a resonant circuit, what is the phase angle between voltage and current? 1. 0 degrees 2. 90 degrees 3. 180 degrees 4. 270 degrees 1-14. In a resonant circuit, how does resistance change, if at all, in response to an increase in frequency? 1. Increases 2. Decreases 3. Remains the same 1-15. In a series-LC circuit, which of the following component characteristics describes circuit action (a) below the resonant frequency and (b) above the resonant frequency?
1. (a) Inductive (b) Capacitive 2. (a) Inductive (b) Resistive 3. (a) Capacitive (b) Inductive 4. (a) Capacitive (b) Resistive
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3 Figure 1A.—Series-resonant circuit.
In Answering Questions 1-16
Through 1-21, Refer To Figure 1A.
1-16. What is the resonant frequency for the circuit? 1. 1.592 MHz 2. 92 MHz 3. 159.2 MHz 4. 1,592 MHz 1-17. What is the value of inductive reactance? 1. 1.97 ohms 2. 97 ohms 3. 199.7 ohms 4. 1,997 ohms 1-18. If the resonant frequency is 7.96 MHz, what is the value of capacitive reactance? 1. 500 ohms 2. 1,000 ohms 3. 2,000 ohms 4. 4,000 ohms
In Answering Questions 1-19
Through 1-21, Assume The Source
Frequency In Figure 1A Is Above
The Resonant Frequency. Select
The Answers That Describe How An
Above-Resonance Frequency Will
Cause The Circuit Characteristics
In The Questions To Respond When
Compared To Their Values At
Resonance.
1-19. Impedance. 1. Increases 2. Decreases 3. Remains the same 1-20. Current. 1. Increases 2. Decreases 3. Remains the same 1-21. Voltage drops across the reactances. 1. Increases 2. Decreases 3. Remains the same
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4 Figure 1B.—Series-resonant circuit curves.
In Answering Questions 1-22 And
1-23, REFER TO FIGURE 1B. 1-22. Response curve B for a series-resonant circuit represents which of the following circuit characteristics? 1. Power 2. Voltage 3. Current 4. Impedance 1-23. At resonance, which of the following series-resonant circuit values is at a maximum value? 1. Circuit current 2. Voltage across L 3. Voltage across C 4. Circuit impedance 1-24. In a series-resonant circuit operating at fr, what term describes the impedance of the circuit? 1. Resistive 2. Inductive only 3. Capacitive only 4. Capacitive-inductive Figure 1C.—Parallel-resonant circuit.
In Answering Questions 1-25
Through 1-27, Refer To Figure 1C.
1-25. In the parallel-resonant circuit, what is the phase relationship between the current in the inductor and the current in the capacitor? 1. Inductor current is in phase with capacitor current 2. Inductor current is 45 degrees out of phase with capacitor current 3. Inductor current is 90 degrees out of phase with capacitor current 4. Inductor current is 180 degrees out of phase with capacitor current 1-26. In the parallel-resonant circuit, what is the phase relationship between voltage in the inductor and the voltage in the capacitor.
1. Inductor voltage is in phase with capacitor voltage 2. Inductor voltage is 45 degrees out of phase with capacitor voltage 3. Inductor voltage is 90 degrees out of phase with capacitor voltage 4. Inductor voltage is 180 degrees out of phase with capacitor voltage 5 1-27. In the parallel-resonant circuit, which of the following circuit conditions is NOT normal? 1. X C equals XL 2. I C equals IL 3. I line is minimum 4. I line is maximum Figure 1D.—Parallel-resonant circuit curves.
In Answering Questions 1-28 And
1-29, REFER TO FIGURE 1D. 1-28. In the figure, what does response curve A represent? 1. Current 2. Impedance 3. Reactance 4. Resistance 1-29. What does response curve B represent? 1. Power 2. Impedance 3. Reactance 4. Resistance 1-30. As a parallel-resonant circuit approaches resonance, which of the following circuit actions takes place? 1. Impedance decreases 2. Oscillating current increases 3. Inductance increases 4. Capacitance decreases 1-31. When a parallel-resonant circuit operates BELOW resonance, which of the following component characteristics describes circuit action?
1. Inductive 2. Capacitive 3. Resistive 1-32. When a parallel-resonant circuit operates ABOVE resonance, which of the following component characteristics describes circuit actions? 1. Inductive 2. Capacitive 3. Resistive 1-33. In a parallel-resonant circuit, which of the following circuit conditions is observed? 1. Oscillating current is less than line current 2. Oscillating current is greater than line current 3. Line current is maximum 4. Impedance is minimum 1-34. What is the level of impedance offered at resonance in (a) a series-resonant circuit and (b) a parallel-resonant circuit?
1. (a) High (b) high 2. (a) High (b) low 3. (a) Low (b) low 4. (a) Low (b) high 1-35. The ability of a resonant circuit to separate currents of desired frequencies from those of undesired frequencies makes them useful in which of the following circuit applications? 1. Filters 2. Counters 3. Amplifiers 4. Voltage dividers 6 1-36. The Q of a circuit is a measure of circuit 1. quality 2. permeance 3. conductance 4. inductive reactance 1-37. Which of the following circuit values has the greatest effect on the figure of merit of the circuit?
1. Reactance 2. Inductance 3. Resistance 4. Capacitance 1-38. What formula is used to figure the Q of a coil? 1. 3. 2. 4. 1-39. On which of the following coil characteristics is the Q of a coil dependent? 1. Size 2. Length 3. Material 4. All of the above
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1-40. A series-resonant circuit, which of the following conditions results in a voltage gain? 1. 2. 3. 4. 1-41. In a parallel-resonant circuit, Q is used to figure which of the following circuit values? 1. Voltage gain 2. Voltage loss 3. Circulating tank current 4. Circulating line current 1-42. To determine bandwidth, you would use which of the following mathematical expressions? 1. 3. 2. 4. 1-43. To calculate (figure) the half-power points of a resonant circuit, which of the following mathematical expressions should you use?
1. .707 x I min 2. .707 x I max 3. .637 x I min 4. .637 x I max 7 Figure 1E.—Response curve.
In Answering Questions 1-44
Through 1-46, Refer To Figure 1E.
1-44. In the response curve, what is the resonant frequency? 1. 50 kHz 2. 70 kHz 3. 100 kHz 4. 140 kHz 1-45. What is the bandwidth? 1. 10 kHz 2. 20 kHz 3. 30 kHz 4. 40 kHz 1-46. If the Q of the circuit represented by the response curve is 100, what is the bandwidth? 1. 1 kHz 2. 10 kHz 3. 20 kHz 4. 30 khz Figure 1F.—Filter circuit.
In Answering Question 1-47, Refer
To Figure 1F.
1-47. If the applied frequency to the circuit is increased, what is the response of (a) XC and (b) XL 1. (a) X C increases (b) X L increases 2. (a) X C increases (b) X L decreases 3. (a) X C decreases (b) X L decreases 4. (a) X C decreases (b) X L increases
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8 _______________________________________
To Answer Questions 1-48 Through
1-50, SELECT FROM COLUMN B THE
Circuit Which Describes The
Circuit Operation In Column A.
Choices In Column B May Be Used
Once, More Than Once, Or Not At
ALL.
A. Circuit
Operation
B. Circuit
1-48. Passes the majority of current below a specific frequency and opposes current above that frequency. 1. 2. 3. 4. Band-pass filter High-pass filter Low-pass filter Band-reject filter 1-49. Passes the majority of current above a specific frequency and opposes current below that frequency. 1-50. Passes a narrow band of frequencies and opposes all others. _______________________________________ 1-51. The action of a filter circuit that reduces the amplitude of unwanted frequencies below the amplitude of the desired frequency is known as 1. attenuation 2. amplification 3. discrimination 4. impedance matching 1-52. The frequency beyond which a filter circuit no longer passes current is referred to as the 1. filter frequency 2. cutoff frequency 3. resonant frequency 4. response frequency
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9 Figure 1G.—Filter circuits.
To Answer Questions 1-53 And 1-54,
Select From Figure 1G The Circuit
Diagram Which Matches The
Circuit Name In Each Question.
Choices In The Figure May Be Used
Once, More Than Once, Or Not At
ALL. 1-53. Band-reject filter. 1. A 2. B 3. C 4. D 1-54. High-pass filter. 1. A 2. B 3. C 4. D Figure 1H.—Filter circuit.
In Answering Questions 1-55 And
1-56, REFER TO THE CIRCUIT IN FIGURE 1H. 1-55. L1 and C1 in the circuit offer what type of opposition to (a) frequencies near resonance and (b) all other frequencies? 1. (a) Minimum (b) minimum 2. (a) Minimum (b) maximum 3. (a) Maximum (b) maximum 4. (a) Maximum (b) minimum 1-56. In the type of filter circuit in the figure, what is/are the "cutoff point(s)?" 1. Upper frequency limit only 2. Lower frequency limit only 3. Both upper and lower frequency limits 1-57. In a series-resonant circuit that is operating at resonance, what is the amplitude of the applied voltage compared to (a) inductor voltage and (b) capacitor voltage?
1. (a) Lower (b) lower 2. (a) Lower (b) higher 3. (a) Higher (b) higher 4. (a) Higher (b) lower 10 Figure 1I.—Series-RCL circuit at resonance.
In Answering Questions 1-58
Through 1-60, Refer To Figure 1I.
1-58. With the circuit in the figure at resonance, what is the circuit current? 1. 1 ampere 2. 2 amperes 3. 3 amperes 4. 0.5 ampere 1-59. If E a were increased to 60 volts at the resonant frequency, what would be the voltage drop across the capacitor? 1. 10 volts 2. 20 volts 3. 30 volts 4. 60 volts 1-60. If the circuit is at resonance, what is circuit impedance? 1. 10 ohms 2. 20 ohms 3. 30 ohms 4. 40 ohms 11
Assignment 2
Textbook assignment: Chapter 2, “Oscillators,” pages 2-1 through 2-38. ___________________________________________________________________________________ 2-1. A sinusoidal oscillator can be regarded as which of the following types of amplifiers? 1. One that produces a trapezoidal wave 2. One that produces a sine wave 3. One that produces a square wave 4. One that produces a sawtooth wave 2-2. Wave generators are classified according to the 1. input wave shape 2. output wave shape 3. current in the output 4. voltage in the output 2-3. An IDEAL sinusoidal oscillator would produce which of the following outputs?
1. A square wave of constant frequency and amplitude 2. A square wave of varying frequency and amplitude 3. A sine wave of constant frequency and amplitude 4. A sine wave of varying frequency and constant amplitude 2-4. What three circuits are most commonly used as frequency determining devices? 1. Class C amplifier, class B amplifier, and class A amplifier 2. Crystal-controlled oscillator, RC oscillator, and LC oscillator 3. Common-emitter amplifier, common- base amplifier, and common-collector amplifier 4. Transformer coupler, RC coupler, and direct coupler 2-5. Which of the following circuits is NOT a relaxation oscillator?
1. A multivibrator 2. A sawtooth generator 3. A blocking oscillator 4. A sinusoidal oscillator 2-6. Which of the following definitions describes the basic oscillator? 1. A nonrotating device producing alternating current 2. A rotating device producing alternating current 3. A nonrotating device producing direct current 4. A rotating device producing direct current 2-7. Amplitude stability in an oscillator is the ability to 1. produce an increased amplitude in the output 2. produce a variable amplitude in the output 3. maintain a constant frequency in the output 4. maintain a constant amplitude in the output 2-8. Frequency stability in an oscillator refer to its ability to 1. maintain a constant operating frequency 2. maintain a variable operating amplitude 3. maintain a constant amplitude 4. vary operating frequency 12 2-9. What is the purpose of a buffer amplifier?
1. To provide a direct connection between the oscillator and the load 2. To amplify the output signal of the oscillator 3. To remove frequency distortion from the oscillator 4. To prevent load variations from affecting the oscillator 2-10. Why is class A bias used in oscillators? 1. To develop low power 2. To develop maximum power 3. To maintain low distortion 4. To maintain high efficiency 2-11. When a group of RC networks is used for regenerative feedback, which of the following waveform actions takes place in each successive stage?
1. Waveform is rectified 2. Amplitude is decreased 3. Amplitude is increased 4. Amplitude is held constant 2-12. When RC networks are connected in cascade (series), what amount of phase shift should you see? 1. The sum of the phase shifts of each RC network 2. The difference between the phase shifts of each RC network 3. The product of the phase shifts of each RC network 4. The square of the phase shifts of each RC network 2-13. Which of the following terms describes the gradual amplitude reduction in an oscillator?
1. Damping 2. Phase shift 3. Regeneration 4. Flywheel effect 2-14. Which of the following formulas can be used to figure frequency in an LC tank circuit? 1. 2. 3. 4. 2-15. Which of the following actions best describes the piezoelectric effect? 1. Produces an dc output voltage for a given ac input voltage 2. Produces an output voltage for a given mechanical input 3. Produces a mechanical output for a given input voltage 4. Both 2 and 3 above 2-16. The piezoelectric effect is the property of a crystal which produces which of the following electrical characteristics?
1. Resistance 2. Inductance 3. Capacitance 4. Each of the above 13 2-17. What is the schematic symbol for a crystal? 1. 2. 3. 4. 2-18. What electrical characteristic makes the frequency stability of a crystal better than that of an LC tank circuit? 1. Higher Q 2. Higher inductance 3. Higher resistance 4. Higher capacitance 2-19. How is feedback described? 1. Control of a circuit output signal by the input signal 2. Control of a circuit input signal by the output of the previous circuit 3. Transfer of a portion of the output circuit energy to control the input of the circuit 4. Transfer of a portion of the input circuit energy to control the output circuit 2-20. Which of the following terms describes the types of feedback?
1. Degenerative and regenerative 2. Negative and positive 3. Both 1 and 2 above 4. Bypassed and unbypassed 2-21. What type of feedback aids an input signal? 1. Positive 2. Negative 3. Bypassed 4. Degenerative 2-22. What type of feedback opposes an input signal? 1. Positive 2. Unbypassed 3. Degenerative 4. Regenerative 2-23. What type of feedback is used to sustain oscillations? 1. Bypassed 2. Negative 3. Degenerative 4. Regenerative 2-24. What oscillator uses a tickler coil for feedback? 1. Hartley 2. Colpitts 3. Armstrong 4. RC phase-shift 2-25. What oscillator uses a tapped coil for feedback?
1. Hartley 2. Colpitts 3. Armstrong 4. RC phase-shift 14 2-26. What oscillator uses split capacitors for feedback? 1. Hartley 2. Colpitts 3. Armstrong 4. RC phase-shift _______________________________________
To Answer Questions 2-27 Through
2-29, SELECT THE CONFIGURATIONS IN
Column B That Match The Amplifier
Characteristics In Column A.
Choices In Column B May Be Used
Once, More Than Once Or Not At All.
A. Characteristics
2-27. Voltage gain is less than unity 2-28. Low power gain 2-29. Feedback signal requires phase shift
B. Configurations
1. Common-base 2. Common-gate 3. Common-emitter 4. Common-collector ______________________________________ 2-30. Which of the following statements best describes tank current in a series-fed oscillator? 1. The dc path is through the tank circuit 2. The dc path does not go through the tank circuit 3. The ac path is through the tank circuit 4. The ac path does not go through the tank circuit 2-31. In a shunt-fed, tuned-collector Armstrong oscillator, what blocks the dc component from the tank circuit? 1. A resistor 2. A capacitor 3. An inductor 4. A transistor 2-32. Which of the following circuit arrangements aid in the frequency stability of an oscillator?
1. A regulated power supply 2. A common bias source for the emitter and collector 3. Both 1 and 2 above 4. Separate bias sources Figure 2A.—Tuned-base Armstrong oscillator.
In Answering Questions 2-33
Through 2-37, Refer To Figure 2A.
2-33. The frequency of the output signal of the oscillator is determined by what components? 1. R1 and L1 2. L2 and C1 3. L3 and C4 4. R3 and C3 2-34. Forward bias for the amplifier is developed by what component? 1. R1 2. R2 3. R3 4. L1 15 2-35. The resonant frequency is tuned to the desired value by what component? 1. C1 2. C2 3. L3 4. L1 2-36. What is the maximum degree of phase shift provided between the base and collector of Q1? 1. 0 degrees 2. 90 degrees 3. 120 degrees 4. 180 degrees 2-37. Temperature stability of the oscillator is improved by what component?
1. R1 2. R2 3. R3 4. C4 2-38. What feature in a Hartley oscillator differs from an Armstrong oscillator? 1. Tickler coil 2. Split inductor 3. Split coupling 4. Split capacitance
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Figure 2B.—Series-fed, tuned-base Hartley oscillator.
In Answering Questions 2-39
Through 2-42, Refer To Figure 2B.
2-39. What components are part of the frequency-determining device of this oscillator? 1. C1, L1, and L2 2. C2, L1, and L2 3. C3, L1, and L2 4. C E, RE, and RB 2-40. What circuit component prevents thermal runaway? 1. L1 2. C E 3. R B 4. R E 2-41. The low resistance of L2 could place a short across the emitter-to-base junction network of Q1 and RE. What component in the circuit prevents this from happening? 1. C1 2. C2 3. C3 4. C E 16 2-42. When a positive signal is coupled to the base of Q1, what happens to (a) collector current and (b) emitter current?
1. (a) Increases (b) increases 2. (a) Increases (b) decreases 3. (a) Decreases (b) decreases 4. (a) Decreases (b) increases 2-43. A tuned-base Hartley oscillator is described as "shunt fed" when 1. ac flows through the tank circuit 2. dc flows through the tank circuit 3. ac does not flow through the tank circuit 4. dc does not flow through the tank circuit 2-44. Which of the following advantages does the Colpitts oscillator have over the Armstrong and Hartley oscillators? 1. Easier to tune 2. Wider frequency range 3. Better frequency stability 4. All of the above
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Figure 2C.—Oscillator.
In Answering Questions 2-45
Through 2-47, Refer To Figure 2C.
2-45. What type of oscillator is shown in the figure? 1. Common-base Hartley 2. Common-base Colpitts 3. Common-emitter Colpitts 4. Common-collector Hartley 2-46. What component is the collector load resistor? 1. R1 2. R2 3. R3 4. R4 2-47. What resistors provide the base bias? 1. R1, R2 2. R2, R3 3. R3, R4 4. R2, R4 17 2-48. What class of biasing does the RC oscillator use? 1. A 2. B 3. C 4. AB 2-49. In an RC network, (a) what type of impedance is presented and (b) does the current lead or lag? 1. (a) Inductive (b) leads 2. (a) Inductive (b) lags 3. (a) Capacitive (b) lags 4. (a) Capacitive (b) leads 2-50. In the phase-shift oscillator, a phase shift of 180 degrees for regenerative feedback is provided by what minimum number of RC networks?
1. One 2. Two 3. Three 4. Four 2-51. What determines the phase angle of an RC network? 1. Input voltage 2. Output voltage 3. Values of resistance and inductance 4. Values of resistance and capacitance
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Figure 2D.—Phase-shift oscillator.
In Answering Questions 2-52
Through 2-56, Refer To Figure 2D.
2-52. What is the maximum amount of phase shift provided by Q1 in the figure? 1. 0 degrees 2. 60 degrees 3. 90 degrees 4. 180 degrees 2-53. What type of feedback is provided through the RC networks to the base of Q1? 1. Neutral 2. Negative 3. Regenerative 4. Degenerative 2-54. At any other than the desired frequency, what type of feedback is provided by the circuit? 1. Neutral 2. Positive 3. Regenerative 4. Degenerative 2-55. What components make up the frequency- determining device? 1. C1, C2, C E, R1, R2, RB 2. C2, C3, C E, R2, RB, RE 3. C1, C2, C3, R1, R2, R B 4. C out, C1, C2, R1, R2, RE 18 2-56. What is the maximum amount of phase shift provided by the C3-RB network?
1. 90 degrees 2. 80 degrees 3. 70 degrees 4. 60 degrees 2-57. Which of the following is the correct formula for the resonant frequency of a phase-shift oscillator? 1. 3. 2. 4. 2-58. Which of the following oscillators is used to provide a highly stable output at a very precise frequency? 1. Crystal 2. Hartley 3. Colpitts 4. Armstrong 2-59. The frequency of a crystal-controlled oscillator is determined by which of the following physical actions? 1. Type of cut 2. Accuracy of cut 3. Thickness of grinding 4. All of the above 2-60. Why is the crystal in a crystal-controlled oscillator often installed in a temperature- controlled oven?
1. To increase frequency without changing the crystal 2. To decrease frequency without changing the crystal 3. To provide better amplitude stability 4. To provide better frequency stability Figure 2E.—Frequency response of a crystal.
In Answering Questions 2-61
Through 2-64, Refer To Figure 2E. The
Letters A, B, C, D, And E Are Points On
The Frequency-Response Curve
From Which You Should Select
Answers To The Questions.
2-61. At what point on the curve does a crystal act as a series-tuned circuit? 1. A 2. B 3. C 4. D 2-62. At what point does the crystal act inductively? 1. A 2. B 3. C 4. D 2-63. Below series resonance, a crystal acts capacitively at what point on the curve? 1. A 2. B 3. C 4. E 2-64. At what point does the crystal act purely as a parallel-resonant circuit? 1. B 2. C 3. D 4. E 19 2-65. How is the Q of a crystal determined? 1. Type of cut used 2. Type of holder used 3. Accuracy of the grinding 4. All of the above 2-66. An oscillator that is turned ON for a specific period of time, then is turned OFF and remains OFF until required at a later time, is which of following types?
1. LC 2. Pierce 3. Pulsed 4. Crystal Figure 2F.—Oscillator circuit.
In Answering Questions 2-67
Through 2-70, Refer To Figure 2F.
2-67. What circuit is shown in the figure? 1. Pierce oscillator 2. Pulsed oscillator 3. Colpitts oscillator 4. Armstrong oscillator 2-68. Sine waves are generated in the emitter circuit of Q1 during which of the following time periods of the input gate? 1. T0 to T1 and T1 to T2 2. T0 to T1 and T2 to T3 3. T1 to T2 and T3 to T4 4. T1 to T3 and T0 to T4 2-69. The frequencies in the output are determined by what two circuit parameters? 1. Input gate time and the time the circuit is turned OFF 2. Output gate time and the time the circuit is turned ON 3. Input gate time and the resonant frequency of the tank circuit 4. Output gate time and the resonant frequency of the tank circuit, 2-70. If the resonant frequency of the tank circuit were 5 megahertz and transistor Q1 were cut off for 500 microseconds, what maximum number of cycles of the tank frequency would be present in each pulse of the output?
1. 500 cycles 2. 1,500 cycles 3. 2,500 cycles 4. 3,500 cycles 2-71. What is the fourth harmonic of a 2-megahertz signal? 1. 6 megahertz 2. 2 megahertz 3. 8 megahertz 4. 4 megahertz 2-72. What is the highest multiplication factor normally used in frequency multipliers? 1. One 2. Two 3. Three 4. Four 20 2-73. As the multiplication factor in a frequency multiplier circuit is increased, what happens to the output signal (a) amplitude and (b) frequency? 1. (a) Increases (b) increases 2. (a) Increases (b) decreases 3. (a) Decreases (b) decreases 4. (a) Decreases (b) increases 2-74. In a buffer amplifier, what is the impedance in the (a) input and (b) output?
1. (a) Low (b) low 2. (a) Low (b) high 3. (a) High (b) high 4. (a) High (b) low 21
Assignment 3
Textbook assignment: Chapter 3, “Waveforms and Wave Generators,” pages 3-1 through 3-56. _____________________________________________________________________________________ 3-1. A waveform that repeats the same pattern of changes is a/an 1. periodic wave 2. sporadic wave 3. aperiodic wave 4. transverse wave 3-2. Which of the following waveforms is sinusoidal? 1. Sine wave 2. Square wave 3. Sawtooth wave 4. Rectangular wave 3-3. The time required to complete one full cycle of a square wave is referred to as the 1. pulse-repetition rate 2. pulse-repetition time 3. pulse-repetition cycle 4. pulse-repetition frequency 3-4. What term(s) describes the number of times in one second that a square wave repeats itself?
1. The pulse-repetition frequency (prf) 2. The pulse-repetition rate (prr) 3. Both 1 and 2 above 4. The pulse-repetition time (prt) 3-5. A square wave with a prf of 1,250 hertz has a prt of 1. 8 microseconds 2. 80 microseconds 3. 800 microseconds 4. 8,000 microseconds
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22 Figure 3A.—Square wave.
In Answering Questions 3-6
Through 3-10, Select The
Corresponding Letter In Figure 3A
Which Describes The Portion Of The
Waveform In Each Of The
Following Questions.
3-6. The leading edge of the pulse. 1. C 2. D 3. E 4. F 3-7. The trailing edge of the pulse. 1. A 2. B 3. C 4. D 3-8. The positive alternation. 1. C 2. D 3. E 4. F 3-9. The amplitude of the pulse. 1. A 2. B 3. C 4. D 3-10. The pulse-repetition time of the pulse. 1. C 2. D 3. E 4. F 3-11. What type of waveform is used to furnish a linear rise in current for electromagnetic cathode ray tubes? 1. Square wave 2. Sawtooth wave 3. Trapezoidal wave 4. Rectangular wave 3-12. Which of the following multivibrators must have a signal applied (triggered) to change states?
1. Astable 2. Bistable 3. Monostable 4. Both 2 and 3 above 3-13. Which of the following multivibrators is also called a free running multivibrator? 1. Astable 2. Bistable 3. Monostable 4. Both 2 and 3 above 3-14. Which of the following waveforms could be the output of the astable multivibrator? 1. Sine wave 2. Sawtooth wave 3. Rectangular wave 4. Trapezoidal wave 23 Figure 3B.—Multivibrator.
In Answering Questions 3-15 And
3-16, REFER TO FIGURE 3B. 3-15. The time necessary for Q2 in the circuit to become saturated is controlled by what RC network? 1. R1, C1 2. R2, C1 3. R3, C2 4. R4, C2 3-16. Which of the following conditions exist in the outputs of the figure from T0 to T1? 1. Q1 saturated, Q2 saturated 2. Q1 saturated, Q2 cutoff 3. Q1 cutoff, Q2 cutoff 4. Q1 cutoff, Q2 saturated 3-17. What multivibrator is a square or rectangular-wave generator with only one stable condition? 1. Astable 2. Bistable 3. Monostable 4. Eccles-Jordan 3-18. What is the primary use for the monostable multivibrator circuit?
1. Filter 2. Amplifier 3. Oscillator 4. Pulse stretcher Figure 3C.—Monostable multivibrator circuit.
In Answering Questions 3-19 And
3-20, REFER TO FIGURE 3C. 3-19. In the stable state of the circuit, what will be the condition of (a) Q1 and (b) Q2? 1. (a) Cutoff (b) cutoff 2. (a) Cutoff (b) saturated 3. (a) Saturated (b) saturated 4. (a) Saturated (b) cutoff 3-20. What is the discharge path for C1? 1. C1, Q2, ground, -V CC, Q1, and C1 2. C1, Q2, ground, +V BB, R5, Q1, and C1 3. C1, Q2, R4, R2, +V BB, -VCC, R2, and C1 4. C1, Q1, ground, -V CC, R2, and C1 24 3-21. In a bistable multivibrator, what minimum number of triggers is required to produce one gate?
1. One 2. Two 3. Three 4. Four 3-22. Which of the flip flops shown below is in the SET state? 1. 2. 3. 4. 3-23. Which of the flip flops shown below is in the CLEAR state? 1. 2. 3. 4. 3-24. Which of the following pulses is used to change states in a flip flop? 1. A trigger pulse 2. A clipping pulse 3. A modulating pulse 4. An interference pulse 25 Figure 3D.—Flip-flop output 1 waveforms.
In Answering Questions 3-25
Through 3-29, Refer To Figure 3D.
Assume The Flip-Flop Is Initially In
The Clear State. Select The
WAVEFORM AT THE "1" OUTPUT IN THE
Figure That Will Result From The
Input Pulses Shown In The
Questions. Some Choices May Be
Used Once, More Than Once, Or Not
AT ALL. 3-25. 1. A 2. B 3. C 4. D 3-26. 1. A 2. B 3. C 4. D 3-27. 1. A 2. B 3. D 4. E 3-28. 1. B 2. C 3. D 4. F 26 3-29. 1. A 2. B 3. E 4. F 3-30. The toggle input on a flip flop is used to cause which of the following circuit actions? 1. SET the flip flop 2. CLEAR the flip flop 3. Both 1 and 2 above 4. Sample the condition of the flip flop 3-31. The blocking oscillator is NOT suitable for which of the following circuit applications? 1. Counter circuit 2. Frequency divider 3. Switching circuit 4. Sine-wave generator
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27 Figure 3E.—Blocking oscillator.
In Answering Questions 3-32
Through 3-37, Refer To Figure 3E.
3-32. What is indicated by the dots at each end of T1 in the figure? 1. 0-degree phase shift 2. 90-degree phase shift 3. 160-degree phase shift 4. 180-degree phase shift 3-33. Regenerative feedback to the base of Q1 is provided by what circuit component(s)? 1. L1 only 2. L2 only 3. L1 and L2 only 4. L1, L2, and C1 3-34. What circuit action is taking place from T0 to T1? 1. C1 is charging 2. C1 is discharging 3. L1 is discharging 4. I C is decreasing 3-35. THIS QUESTION HAS BEEN DELETED. 3-36. During what total time period is Q1 blocked?
1. T0 to T1 2. T1 to T2 3. T0 to T2 4. T2 to T3 3-37. In the blocking oscillator, which of the following circuit actions is the primary cause of parasitic oscillations? 1. Collapse of the magnetic field of L1 2. Expansion of the magnetic field of L1 3. Inductive coupling between L1 and L2 4. C1 discharging through Q1 3-38. Which of the following circuit actions is a result of critical damping? 1. Rapid transient response without overshoot 2. Rapid transient response with overshoot 3. Slow transient response without overshoot 4. Slow transient response with overshoot 3-39. What type of damping is caused by (a) high resistance and (b) low resistance?
1. (a) Overdamping (b) Underdamping 2. (a) Underdamping (b) Overdamping 3. (a) Critical damping (b) Underdamping 4. (a) Overdamping (b) Critical damping 28 3-40. Applying synchronizing triggers with a frequency that is SLIGHTLY higher than the free-running frequency will cause a synchronized blocking oscillator to 1. divide in frequency 2. double in frequency 3. lock in at the higher frequency 4. stay locked at the free-running frequency Figure 3F.—Sawtooth waveform.
In Answering Questions 3-41
Through 3-46, Refer To Figure 3F
And Match The Waveform Points
(OR TIME REFERENCES) TO THE TERMS
In The Questions. Some Choices
May Be Used Once, More Than Once,
Or Not At All.
3-41. Linear slope. 1. A to B 2. B to C 3. T0 to T2 4. T1 to T2 3-42. Physical length. 1. A to B 2. B to C 3. X 4. Y 3-43. Sweep time. 1. A to B 2. B to C 3. T0 to T1 4. T1 to T2 3-44. Fall time. 1. A to C 2. T0 to T1 3. T1 to T2 4. T0 to T2 3-45. Electrical length. 1. B to C 2. T0 to T1 3. T1 to T2 4. T0 to T2 3-46. Amplitude. 1. A to B 2. B to C 3. X 4. Y 3-47. The linearity of the rise voltage in a sawtooth wave is determined by which of the following circuit timing actions? 1. The time the capacitor is allowed to charge 2. The time it takes the capacitor to fully charge 3. The time the capacitor is allowed to discharge 4. The time it takes the capacitor to fully discharge 29 Figure 3G.—Transistor sawtooth generator.
In Answering Questions 3-48
Through 3-53, Refer To Figure 3G.
3-48. What component in the circuit develops the output sawtooth waveform? 1. R1 2. R2 3. C1 4. C2 3-49. What is the purpose of Q1? 1. Acts as a switch 2. Allows C2 to charge 3. Inverts the negative gate 4. Serves as a common-collector amplifier 3-50. What is the maximum length of time C2 is allowed to charge? 1. 200 microseconds 2. 500 microseconds 3. 700 microseconds 4. 900 microseconds 3-51. If V CC were increased to 40 volts, which of the following parameters in the output sawtooth wave would increase? 1. Fall time 2. Amplitude 3. Sweep time 4. Linearity 3-52. What would be the effect on C2 if the negative gate length were increased?
1. Charge to V CC 2. Discharge to V CC 3. Charge to a larger percentage of V CC 4. Charge to a smaller percentage of V CC 3-53. What is the prf of the circuit? 1. 1,428 pulses per second 2. 1,450 pulses per second 3. 1,470 pulses per second 4. 1,482 pulses per second 3-54. In a sawtooth generator, a change in which of the following parameters will NOT affect the linearity of the output? 1. V CC 2. Resistance 3. Capacitance 4. Gate length
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30 Figure 3H.—Unijunction sawtooth generator.
In Answering Questions 3-55
Through 3-59, Refer To Figure 3H.
3-55. The output in the circuit is taken across what component. 1. R1 2. B2 3. R1 4. C1 3-56. What is the discharge path for C1? 1. C1, R1, V CC, ground, and C1 2. C1, emitter B2, V CC, ground, and C1 3. C1, B1, emitter, and C1 4. C1, B1, B2, V CC, ground, and C1 3-57. What part of the waveform is sweep time? 1. A to D 2. B to C 3. C to D 4. C to E 3-58. What is the action of C1 when the emitter-to-B1 junction is (a) reverse biased and (b) forward biased? 1. (a) Charging (b) Discharging 2. (a) Discharging (b) Charging 3. (a) Charging (b) Charging 4. (a) Discharging (b) Discharging 3-59. To obtain a more stable output frequency, you could modify the circuit by applying (a) what type of triggers to (b) what circuit element.
1. (a) Positive (b) B1 2. (a) Positive (b) B2 3. (a) Negative (b) B2 4. (a) Negative (b) B1
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31 Figure 3I.—Transistor sawtooth generator.
In Answering Questions 3-60
Through 3-64, Refer To Figure 3I.
3-60. With no input voltage applied to the circuit, what voltage should you read at the collector? 1. -20 volts 2. -17.5 volts 3. -2.5 volts 4. 0 volts 3-61. To what voltage is C1 allowed to charge? 1. 0 volts 2. -2.5 volts 3. -4.5 volts 4. -20 volts 3-62. To determine the percent of charge on C1, what formula is used? 1. 2. 3. 4. 3-63. Which of the following actions will improve the linearity of the sawtooth? 1. Increasing the value of C1 2. Increasing the value of R1 3. Increasing the gate length 4. Each of the above 3-64. What is the maximum amplitude of the output sawtooth signal?
1. 1.75 volts 2. 2.0 volts 3. 2.5 volts 4. 4.5 volts 3-65. If applied to a coil, what voltage waveform will cause a linear rise in current? 1. Square wave 2. Sawtooth wave 3. Rectangular wave 4. Trapezoidal wave 32 Figure 3J.—Trapezoidal waveform.
In Answering Questions 3-66
Through 3-70, Refer To Figure 3J And
Match The Waveform Points (Or
Time References) To The Terms In
The Questions. Some Choices May
Be Used Once, More Than Once, Or
Not At All.
3-66. Pulse-repetition time (prt). 1. T1 to T2 2. T0 to T3 3. A to B 4. B to C 3-67. Physical length. 1. T0 to T3 2. A to B 3. B to C 4. C to D 3-68. Electrical length. 1. T0 to T1 2. T1 to T2 3. T0 to T3 4. A to B 3-69. Jump voltage. 1. T0 to T1 2. T1 to T2 3. T0 to T3 4. A to B 3-70. Linear slope. 1. C to D 2. B to C 3. A to B 4. T0 to T3
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33 Figure 3K.—Trapezoidal-wave generator with input and output waveforms.
In Answering Questions 3-71
Through 3-74, Refer To Figure 3K.
3-71. The amplitude of the jump voltage is approximately and the amplitude of the trapezoidal wave is 1. (a) 0.5 volts (b) 5 volts 2. (a) 0.5 volts (b) 0.5 volts 3. (a) 5 volts (b) 0.5 volts 4. (a) 5 volts (b) 5 volts 3-72. Which of the following components and/or value(s) determines the amplitude of the jump voltage? 1. V CC only 2. R2 and V CC only 3. R3 and V CC only 4. R2, R3, and V CC 3-73. What is the minimum discharge time for C2? 1. 50 microseconds 2. 500 microseconds 3. 1,000 microseconds 4. 2,000 microseconds 3-74. Increasing which of the following values will NOT affect linearity of the circuit?
1. Resistance of R2 2. Capacitance of C2 3. Gate width 4. V CC 34
Assignment 4
Textbook assignment: Chapter 4, “Wave Shaping,” pages 4-1 through 4-61. _____________________________________________________________________________________ 4-1. A wave-shaping circuit which restricts some portion of a waveform from exceeding a specified value is known as a/an 1. divider 2. clamper 3. limiter 4. oscillator 4-2. Limiting circuits are used in which of the following circuit applications? 1. Counting 2. Amplification 3. Wave generation 4. Circuit protection 4-3. In a series limiter, the diode is connected in With the 1. (a) Parallel (b) output 2. (a) Parallel (b) input 3. (a) Series (b) input 4. (a) Series (b) output 4-4. In a series limiter, a voltage is developed across the output resistor when 1. the anode of the diode is negative with respect to the cathode 2. the anode of the diode is positive with respect to the cathode 3. the cathode of the diode is positive with respect to the anode 4. no current flows through the diode 4-5. The diode in a series-positive limiter is (a) forward biased by what portion of the input signal and (b) reverse biased by what portion of the input signal?
1. (a) Positive (b) positive 2. (a) Positive (b) negative 3. (a) Negative (b) negative 4. (a) Negative (b) positive 4-6. How does the value of diode resistance compare to that of the resistor (a) during the limiting portion of the input and (b) during the nonlimiting portion? 1. (a) High (b) high 2. (a) High (b) low 3. (a) Low (b) low 4. (a) Low (b) high 4-7. Which of the following circuits is a series-positive limiter? 1. 3. 2. 4. 35 4-8. If a sine wave is applied to the input of a series-positive limiter, which of the following waveforms describes the output?
1. 3. 2. 4. 4-9. The amplitude of the output of a series- diode limiter is figured using which of the following formulas? 1. 2. 3. 4. ____________________________________
In Answering Questions 4-10 And
4-11, ASSUME YOU ARE FIGURING
Output Amplitudes For Series-
Positive Limiters And Circuit
CONDITIONS ARE AS FOLLOWS: Ein = 30 vac R1 = 20,000Ω Rac = 100 Ω (forward bias) Rac = 150,000Ω (reverse bias) ____________________________________ 4-10. With forward bias, what is the output amplitude? 1. 28.95 volts 2. 29 volts 3. 29.85 volts 4. 29.95 volts 4-11. With reverse bias, what is the output amplitude? 1. .175 volt 2. 1.75 volts 3. 3.53 volts 4. 3.75 volts 4-12. In a series-positive limiter, where is the input signal applied? 1. Directly to the anode of the diode 2. Directly to the cathode of the diode 3. To the anode of the diode through a series input resistor 4. To the cathode of the diode through the output resistor 36 4-13. With a sine wave applied, which of the following circuits limits only a portion of the positive input signal?
1. Series-negative limiter with negative bias 2. Series-negative limiter with positive bias 3. Series-positive limiter with negative bias 4. Series-positive limiter with positive bias 4-14. With a sine-wave input, which of the following types of series limiter allows only a portion of the negative input to be developed in the output? 1. Series-positive limiter without bias 2. Series-positive limiter with negative bias 3. Series-positive limiter with positive bias 4. Series-negative limiter without bias 4-15. In a series-negative limiter, how is the diode biased (a) by the positive half of the input sine wave and (b) by the negative half?
1. (a) Reverse (b) forward 2. (a) Reverse (b) reverse 3. (a) Forward (b) reverse 4. (a) Forward (b) forward
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Intentionally.
Figure 4A.—Sine-wave input.
In Answering Question 4-16, Refer
To Figure 4A.
4-16. If the input waveform shown in the figure is applied to a series-negative limiter, which of the following waveforms will be the output? 1. 3. 2. 4. 4-17. In a series-negative limiter with positive bias, which of the following output circuit actions takes place? 1. Both positive half cycles are eliminated 2. Both negative half cycles are eliminated 3. All of the positive half cycles and a portion of the negative half cycles are eliminated 4. All of the negative half cycles and a portion of the positive half cycles are eliminated 37 ____________________________________
In Questions 4-18 Through 4-22,
Match The Limiter Circuit In
Column A To The Circuit
Description In Column B. Choices
May Be Used Once, More Than Once,
Or Not At All.
A. Limiter
CIRCUIT 4-18. 1. A 2. B 3. C 4. D 4-19. 1. A 2. B 3. E 4. F
B. Circuit
Description
A. Series-positive limiter with no bias B. Series-negative limiter with no bias C. Series-positive limiter with negative bias D. Series-positive limiter with positive bias E. Series-negative limiter with negative bias F. Series-negative limiter with positive bias 4-20. 1. C 2. D 3. E 4. F 4-21. 1. C 2. D 3. E 4. F 4-22. 1. C 2. D 3. E 4. F _______________________________________ 4-23. In a parallel-diode limiter, (a) how is the output taken and (b) under what diode condition is it developed? 1. (a) Across the resistor (b) When the diode is cut off 2. (a) Across the resistor (b) When the diode is conducting 3. (a) Across the diode (b) When the diode is conducting 4. (a) Across the diode (b) When the diode is cut off 4-24. In a parallel-positive limiter, where is the input sine wave applied?
1. At the anode of the diode 2. At the cathode of the diode 3. Through a series resistor to the anode of the diode 4. Through a series resistor to the cathode of the diode 38 4-25. Which of the following formulas is used to figure the output amplitude of a parallel-diode limiter? 1. 2. 3. 4. 4-26. THIS QUESTION HAS BEEN DELETED. 4-27. THIS QUESTION HAS BEEN DELETED. 4-28. In a parallel-negative limiter, how is the diode biased (a) by the positive half of the input sine wave and (b) by the negative half? 1. (a) Forward (b) forward 2. (a) Forward (b) reverse 3. (a) Reverse (b) reverse 4. (a) Reverse (b) forward 4-29. If a sine wave is applied to a parallel- negative limiter with positive bias, what is the polarity of the output voltage?
1. Positive at all times 2. Negative at all times 3. Positive during the positive portion of the input cycle and negative during the negative portion 4. Negative during the positive portion of the input cycle and positive during the negative portion Figure 4B.—Parallel-limiter input and output waveforms.
In Answering Question 4-30, Refer
To Figure 4B.
4-30. If the diode in the parallel limiter were reversed, what portions of the input waveform would be limited? 1. Positive peaks only 2. Negative peaks only 3. All hut the positive peaks would be limited 4. All but the negative peaks would be limited 4-31. Which of the following circuits would be used to fix the upper or lower extremity of a waveform at a specific value? 1. Clamper 2. Limiter 3. Counter 4. Amplifier 39 Figure 4C.—Positive clamper.
In Answering Questions 4-32 And
4-33, REFER TO FIGURE 4C. 4-32. When a negative input signal is present, what components provide(s) the charge path for the capacitor? 1. Diode only 2. Resistor only 3. Both the resistor and diode 4-33. How does the length of time required for the capacitor to charge compare to the time for it to discharge? 1. Charge time is longer than discharge time 2. Charge time is shorter than discharge time 3. Charge and discharge times are the same 4-34. In a positive clamper with positive bias, (a) what extremity of the waveform is clamped and (b) to what potential is it clamped?
1. (a) Upper (b) positive 2. (a) Upper (b) negative 3. (a) Lower (b) positive 4. (a) Lower (b) negative 4-35. In a positive clamper with negative bias, (a) what extremity of the waveform is clamped and (b) to what potential is it clamped? 1. (a) Upper (b) positive 2. (a) Upper (b) negative 3. (a) Lower (b) negative 4. (a) Lower (b) positive Figure 4D.—Clamper with bias.
In Answering Questions 4-36 And
4-37, REFER TO FIGURE 4D. 4-36. With +10 volts of bias in the circuit, what is the maximum negative output voltage? 1. -15 volts 2. -25 volts 3. -40 volts 4. -50 volts 4-37. With -15 volts of bias, to what voltage level is the output clamped? 1. +75 volts 2. +45 volts 3. -15 volts 4. -75 volts 40 Figure 4E.—Clamper circuits.
In Answering Questions 4-38
Through 4-40, Select The Circuit In
Figure 4E That Matches The Circuit
Named In The Questions. Choices
May Be Used Once, More Than Once,
Or Not At All.
4-38. Positive clamper with negative bias. 1. A 2. B 3. C 4. D 4-39. Negative clamper with negative bias. 1. A 2. B 3. C 4. D 4-40. Positive clamper with positive bias. 1. A 2. B 3. C 4. D Figure 4F—Clamper circuit outputs.
In Answering Questions 4-41
Through 4-43, Select The Output In
Figure 4F Which Is Produced By The
Circuits In The Questions. Choices
May Be Used Once, More Than Once,
Or Not At All.
4-41. Positive clamper with positive bias. 1. A 2. B 3. C 4. D 4-42. Negative clamper with positive bias. 1. A 2. B 3. C 4. D 4-43. Negative clamper with negative bias. 1. A 2. B 3. C 4. D 41 4-44. Which of the following waves is NOT a complex wave? 1. Sine wave 2. Square wave 3. Rectangular wave 4. Trapezoidal wave 4-45. What is the harmonic content of a square wave? 1. A combination of odd harmonics only 2. A combination of even harmonics only 3. Both even and odd harmonic combinations 4-46. What is the harmonic composition within a sawtooth wave?
1. Odd harmonics only 2. Even harmonics only 3. Both even and odd harmonics 4-47. With a square wave applied to a resistive network, the circuit values of what components will NOT affect either the phases or amplitudes of the harmonics within the square wave? 1. Inductors 2. Resistors 3. Capacitors 4. Transformers 4-48. The time constant for full integration in an RC circuit should be what minimum number of times greater than the input- pulse duration? 1. 1 2. 5 3. 10 4. 20 4-49. Integration in a circuit takes place when the output is taken (a) across the capacitor in what type of circuit and (b) across the resistor in what type of circuit?
1. (a) Resistive only (b) Resistive only 2. (a) Resistive only (b) Resistive-inductive 3. (a) Resistive only (b) Resistive-capacitive 4. (a) Resistive-capacitive (b) Resistive-inductive 4-50. In an RC integrator, which of the following waveforms has the longest time constant? 1. 3. 2. 4. 42 4-51. In an RC differentiator, which of the following waveforms has the shortest time constant? 1. 2. 3. 4. 4-52. In a short time-constant integrator circuit, the maximum amplitude of the input pulse is 100 volts and the time constant of the circuit is 1/10 the duration of the input pulse. At the end of three time constants, what is the maximum voltage across the capacitor?
1. 36.8 volts 2. 63.2 volts 3. 86.5 volts 4. 95 volts 4-53. In a medium time-constant circuit, the maximum amplitude of the input pulse is 100 volts and the pulse length is one time constant. At the end of two time constants, what is the maximum voltage across the capacitor? 1. 23.3 volts 2. 48.4 volts 3. 71.7 volts 4. 100 volts 4-54. In a short time-constant differentiator circuit, the maximum amplitude of the input pulse is 100 volts and the time constant of the circuit is 1/10 that of the input pulse. At the end of four time constants, what is the maximum voltage across the resistor?
1. 5 volts 2. 2 volts 3. 23.3 volts 4. 48.4 volts 4-55. In an RC differentiator circuit, the time constant for the circuit and the input pulse are equal. At the end of one time constant, to what maximum percentage of the applied voltage is the capacitor charged? 1. 5 percent 2. 13.5 percent 3. 36.8 percent 4. 63.2 percent 4-56. In an RC network that is used as a coupling circuit, (a) across what component is the output normally taken and (b) what is the relative length of the time constant? 1. (a) Capacitor (b) short 2. (a) Capacitor (b) long 3. (a) Resistor (b) long 4. (a) Resistor (b) short 43 4-57. In a positive-diode counter that provides accurate counting, what is the only variable allowed in the input signal?
1. Pulse width 2. Pulse duration 3. Pulse amplitude 4. Pulse-repetition frequency Figure 4G.—Basic frequency counter.
In Answering Questions 4-58
Through 4-60, Refer To Figure 4G.
4-58. An input signal to the counter will cause (a) what capacitor to charge through R1 and D2 and (b) what capacitor to discharge through D1? 1. (a) C1 (b) C1 2. (a) C1 (b) C2 3. (a) C2 (b) C1 4. (a) C2 (b) C2 4-59. What components produce the smooth dc output-voltage level? 1. C1, D1, and R1 2. C1, D2, and R1 3. C1, C2, and R1 4. C2, C3, and R2 4-60. When the input frequency is increased, what is the effect on (a) the input interval, (b) the number of pulses per given time and (c) the dc output voltage? 1. (a) Longer (b) less (c) higher 2. (a) Longer (b) more (c) lower 3. (a) Shorter (b) less (c) higher 4. (a) Shorter (b) more (c) higher Figure 4H.—Step-counter frequency divider.
In Answering Questions 4-61 And
4-62, REFER TO FIGURE 4H. 4-61. An output pulse will occur when the charge on C2 1. builds a magnetic field in the base winding 2. drops below the cutoff-bias level of Q1 3. exceeds the bias level of Q1 4. reaches the source potential of the voltage applied 4-62. What component develops the bias for Q1? 1. R1 2. R2 3. C2 4. T1