What is alternating current (AC)?

Alternating current (AC) is a type of electric current whose polarity reverses periodically and whose amplitude varies continuously over time. AC power is often used in businesses and homes because it is cheaper and more efficient to generate and transmit than direct current (DC) power. During transmission, a transformer can reduce power losses by increasing or decreasing the voltage of the AC line.

Alternating current (AC) is a form of household electricity - it is used when consumers plug household appliances such as televisions and other devices into wall outlets. AC power can be converted to direct current for use in almost any electronic device.