Electronics MCQ|MCQ's Basic Electronics

1. When a diode is forward-biased, the anode voltage

(a) is negative relative to the cathode voltage.

(b) is positive relative to the cathode voltage.

(d) alternates between positive and negative relative to the cathode voltage.

2. If a diode is connected in series with the secondary winding of an ac transformer, and if the peak voltage across the diode never exceeds the avalanche voltage, then the output of the complete

transformer-diode circuit is

(a) ac with half the frequency of the input.

(b) ac with the same frequency as the input.

(d) none of the above.

3. A crystal set

(a) can be used to transmit radio signals.

(b) requires a battery with long life.

(d) is used for rectifying 60-Hz ac.

4. A diode detector

(a) is used in power supplies.

(b) is employed in some radio receivers.

(d) changes dc into ac.

5. If the output wave in a circuit has the same shape as the input wave, then

(a) the circuit is operating in a linear manner.

(b) the circuit is operating as a frequency multiplier.

(d) the circuit is operating as a rectifier.

6. Suppose the two input signal frequencies to a mixer circuit are 3.522 MHz and 3.977 MHz. At which of the following frequencies can we expect a signal to exist at the output?

(a) 455 kHz

(b) 886 kHz

(d) 1.129 MHz

7. Fill in the blanks to make the following sentence correct: “A spectrum analyzer provides a display of as a function of .”

(a) amplitude/time

(b) time/frequency

(d) amplitude/frequency

8. Zener voltage is a specialized manifestation of (a) forward breakover voltage.

(b) peak forward voltage.

(d) reverse bias.

9. The forward breakover voltage of a silicon diode is

(a) about 0.3 V.

(b) about 0.6 V.

(d) dependent on the avalanche voltage.

10. A diode audio limiter circuit

(a) is useful for voltage regulation.

(b) always uses Zener diodes.

(d) can cause distortion under some conditions.

11. The capacitance of a varactor varies with the

(a) forward voltage.

(b) reverse voltage.

(d) forward breakover voltage.

12. The purpose of the I layer in a PIN diode is to

(a) minimize the junction capacitance.

(b) optimize the avalanche voltage.

(d) increase the current through the diode.

13. Which of these diode types can be used as the key element in the oscillator circuit of a microwave radio transmitter?

(a) A rectifier diode

(b) A PIN diode

(d) None of the above

14. A Gunnplexer is often used as a

(a) microwave communications device.

(b) low-frequency RF detector.

(d) signal mixer or frequency divider.

15. The most likely place you would find an LED would be in

(a) a rectifier circuit.

(b) a mixer circuit.

(d) an oscillator circuit.

16. Coherent electromagnetic radiation is produced by a

(a) Gunn diode.

(b) varactor diode.

(d) laser diode.

17. Suppose you want a circuit to operate in a stable manner when the load impedance varies. You might consider a coupling method that employs

(a) a Gunn diode.

(b) an optoisolator.

(d) a PIN diode.

18. The electrical power that a solar panel can provide in direct sunlight depends on all of the following factors except

(a) the ac voltage applied to the panel.

(b) the total surface area of all the cells in the panel.

(d) the intensity of the sunlight that strikes the cells.

19. Emission of energy in an IRED is caused by

(a) high-frequency radio waves.

(b) rectification.

(d) none of the above.

20. A photodiode, when not used as a photovoltaic cell, has

(a) reverse bias.

(b) no bias.

(d) negative resistance.

1. b 2. d 3. c 4. b 5. a 6. a 7. d 8. c 9. b 10. d 11. b 12. a 13. c 14. a 15. c 16. d 17. b 18. a 19. c 20. a

Electronics MCQ|MCQ's Basic Electronics