alternating-current transmission

Alternating current (AC) is an electric current that periodically reverses direction. It flows from zero to a maximum, back to zero, then to a maximum in the opposite direction, and repeats this cycle. The time for one cycle is the period, and the number of cycles per second is the frequency, measured in hertz (Hz). Low frequencies (50-60 Hz) are used for power, while higher frequencies are used in communication technologies like television and radar.1

AC has a significant advantage over direct current (DC) for transmitting power over long distances. Power loss due to resistance is proportional to the square of the current. AC systems use transformers to easily change voltage, allowing power to be transmitted at very high voltages and low current, minimizing energy loss. This contrasts with early DC systems, which could only transmit power over short distances due to high current and significant energy loss. Electric power is generated by converting other forms of energy, such as mechanical or thermal, using electric generators.12