| C | H | A | P | T | E | R 23 |
| Alternating Current Circuits |

Alternating current (ac) circuits are the most common kind in use today and include the circuits that distribute electric power throughout the country. Transmission towers such as those in the photograph are part of the power distribution system and the wires attached to them carry ac electricity. (Lester Lefkowitz/The Image Bank/Getty Images)

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