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# Electronics Information for ASVAB Power Practice Problems (page 2)

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Updated on Aug 12, 2011

1. b.   LED stands for light emitting diode.
2. c.   Ohm's law deals with the relationship among voltage, current, and resistance in an electrical circuit.
3. d.   The science of electronics is the use of the controlled motion of electrons through different media such as a vacuum, in gaseous media, or in semiconductors.
4. d.   Two important elements of an electrical device are the conductor and the insulator. A semiconductor allows electrical conductivity between these two items.
5. c.   By definition, a series circuit must have more than one resistor.
6. a.   The antenna captures the radio waves and transforms them, the tuner selects one of the captured signals, the detector separates the audio signal from the radio signal, the amplifier makes the audio signal loud enough to hear, and the speakers transform the audio signal to sound.
7. b.   The equation for Ohm's Law is V = I × R. V represents voltage, I represents current, and R represents resistance.
8. c.   Resistance restricts the flow of electricity. The type of circuit (AC or DC) determines in part the direction of the flow of electricity (choice a). A switch (when open) will stop the flow of electricity (choice b).
9. b.   Increasing the resistance in a circuit will cause the voltage to increase.
10. c.   Joule's Law allows you to calculate the level of power in watts that is generated in a component based on the voltage in volts and the current in amps (P = V × I).
11. d.   In a series circuit, when one bulb no longer works, it acts as an open switch and stops all the other bulbs from working.
12. d.   A transistor is a semiconductor device that amplifies a signal.
13. a.   A capacitor is a passive device that stores electrical energy from a voltage source.
14. b.   The resistor voltage will decrease as the capacitor voltage increases, which in turn decreases the current.
15. b.   Certain types of crystals, such as quartz and Rochelle salts, are mechanically vibrated or altered, causing them to generate a voltage. Piezoelectric devices are used in a wide spectrum of consumer devices such as quartz time pieces, the autofocus mechanism in cameras, and inkjet printers where the piezoelectric effect is used to control the flow of ink from the inkjet head to the paper.
16. d.   An RC circuit, or resistor-capacitor circuit, is composed of resistors and capacitors driven by a voltage or current source and can be used to filter a signal by blocking certain frequencies while allowing others.
17. c.   This schematic symbol represents an LED. The other symbols represent: (a) a diode, (b) a light sensitive diode, and (d) a zener diode.
18. b.   All transistors have a base, emitter, and collector.
19. d.   Voltages in series are added to determine the total voltage. 1.5 V + 1.5 V + 1.5 V + 1.5 V = 6.0 V.
20. d.   A transistor is used to switch or amplify electronic signals.