are equally illuminated, the lamp I 1

Transcription

1 Student ID: Exam: RR - PRACTICAL EXERCISE ADVANCED ELECTRONIC COMPONENTS When you have completed your exam and reviewed your answers, click Submit Exam. Answers will not be recorded until you hit Submit Exam. If you need to exit before completing the exam, click Cancel Exam. Questions 1 to 20: Select the best answer to each question. Note that a question and its answers may be split across a page break, so be sure that you have seen the entire question and all the answers before choosing an answer. 1. Look at the amplifier circuit shown above. Which of the following statements about this circuit is correct? A. This is a common-collector circuit that's characterized by a low input impedance and a high output impedance. B. This is a common-emitter circuit that's characterized by a high input impedance and a low output impedance. C. This is a common-collector circuit that's characterized by a high input impedance and a low output impedance. D. This is a common-emitter circuit that's characterized by a low input impedance and a high output impedance. 2. Look at the circuit diagram shown in the figure above. When R 1 and R 2 are equally illuminated, the lamp I 1 glows dimly. Which of the following will happen if R 2 is covered so that no light can reach it? A. Lamp I 1 glows brighter, because the forward bias on Q 1 is decreased. B. Lamp I 1 goes out, because the forward bias on Q 1 is decreased.

2 C. Lamp I 1 goes out, because the forward bias on Q 1 increases. D. Lamp I 1 glows brighter, because the voltage on the base of Q 1 goes positive. 3. Look at the circuit diagram that's shown in the figure above. What is the voltage between point A and ground? A. +25 V B. +6 V C. 6 V D. 25 V 4. The output voltage of a power supply is measured at 12 V with no load connected. The manufacturer's specifications say the power supply has a regulation of 10 percent. What is the full-load output voltage of the power supply? A V B. 1.2 V C V D V

3 9. Two electronics technicians are discussing LC and RC oscillators. Technician A says that an RC oscillator doesn't require a resonant circuit. Technician B says that an LC oscillator can be tuned only by varying the inductance, and that an RC oscillator can't produce a sine wave. Which of the following statements is correct? 5. Look at the circuit diagram and the four waveforms that are shown in the figure above. Assume that diode D 1 in the circuit is opened. Which of the four waveforms shown in the figure would appear across R L? A. Waveform 3 B. Waveform 4 C. Waveform 1 D. Waveform 2 6. Which of the following is essential for the operation of an oscillator? A. An LC circuit B. A unity gain amplifier C. Degenerative feedback D. Positive feedback 7. A 100 khz oscillator that's followed by a doubler and two triplers will produce an output frequency of A. 500 khz. B. 180 khz. C. 1.8 MHz. D. 800 khz. 8. Negative clipping of an output signal occurs when the A. output impedance is too high. B. power supply voltage is too high. C. input impedance is too high. D. input amplitude is too high.

4 A. Both of the technicians are correct. B. Only Technician B is correct. C. Only Technician A is correct. D. Neither of the two technicians is correct. 10. In the circuit shown in the figure above, what is the current through R 2? A. 2.5 ma B. 25 ma C. 60 ma D. 6.0 ma

5 11. Look at the figure above. Which of the following circuits is a properly biased common-emitter circuit? A. Circuit B B. Circuit A C. Circuit D D. Circuit C 12. Two electronics technicians are comparing a full-wave bridge rectifier to a full-wave rectifier that uses two diodes and a center-tapped secondary. Technician A says that the two-diode rectifier has a lower ripple frequency and can supply greater current than the full-wave bridge rectifier. Technician B says that the fullwave bridge rectifier results in full secondary voltage at the output. Which of the following statements is correct? A. Both of the technicians are correct. B. Only Technician A is correct. C. Only Technician B is correct. D. Neither of the two technicians is correct. 13. A full-wave power supply with a capacitor-input filter is connected to a 400 Hz AC source. The frequency of the ripple waveform at the input to the filter is A. 100 Hz. B. 400 Hz. C. 800 Hz.

6 D. 0 Hz (DC). 14. Look at the circuit diagram shown in the figure above. What is the power level at point B in the circuit? A. 62 mw B. 620 mw C. 3.1 mw D mw 15. Look at the circuit diagram and the four waveforms that are shown in the figure above. Assume that the circuit's switch is closed momentarily, then opened. Which of the four waveforms shown will appear between terminals A and B after the switch is opened? A. Waveform 4 B. Waveform 1 C. Waveform 3 D. Waveform 2

7 16. Look at the four circuit diagrams that are shown above. Which of these four diagrams represents a correctly configured full-wave bridge rectifier circuit? A. Circuit 3 B. Circuit 1 C. Circuit 4 D. Circuit A modulation technique that's used in fiber-optic transmission in which the width of pulses is varied in accordance with the modulation signal is called A. PWM. B. PAM. C. PRM. D. PPM. 18. One advantage of using photon coupling for signal transmission is the A. lower cost of signal-handling components. B. lower power required for transmission. C. greater immunity to noise pickup. D. greater adaptability to digital transmission. 19. What would happen at the output of a full-wave bridge rectifier circuit if one of the diodes in the bridge opened? A. The ripple frequency would remain the same, and the voltage would decrease. B. The ripple frequency would increase, and the voltage would decrease. C. The ripple frequency would decrease, and the voltage would decrease. D. The ripple frequency would remain the same, and the voltage would increase.

8 20. In the circuit shown in the figure above, what is the power level at point A? A mw B. 31 mw C. 3.1 mw D. 310 mw End of exam