Alternating current (AC) refers to an electric current that periodically reverses direction within a circuit, while direct current (DC) flows consistently in a single direction. In the United States, AC switches direction at a frequency of 60 Hz (Cycles/second). The most common AC waveform is the sine wave, but square and triangular waves are also forms of AC.
A specialized generator, known as an AC generator, is designed to produce alternating current. It operates with a rotating magnet (called the rotor) and a stationary coil around an iron core (called the stator). When the rotor spins, it induces an electromotive force in the stator, generating AC voltage. AC power is commonly used to supply electricity to homes and offices, as well as to power motors in appliances like dishwashers and refrigerators.
Generating and transmitting AC power over long distances is relatively straightforward. Power companies use high voltages to enable efficient long-distance power transfer. AC voltage can be easily increased or decreased using transformers, allowing electricity to be safely delivered from power plants to homes.
First, electricity is generated by large generators using wind, coal, natural gas, or hydropower. Then, AC voltage is increased through transformers for transmission. High-voltage power lines carry the current to substations, where the voltage is reduced before distribution. Finally, smaller transformers lower the voltage for safe household use.
Some devices require an AC adapter, which uses another transformer to convert the current received by the power outlet into a lower AC current that the electronic device can use. The number of transformers the current must pass through depends on the maximum amount of current the electronic device can handle.
