Alternating current (AC) is a type of electrical current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. AC is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, fans, and electric lamps into a wall socket.
Some key features of AC include:
- Periodic Reversal: AC voltage or current changes polarity or direction, respectively, over time.
- Delivery of Electric Power: AC is the form in which electric power is delivered to businesses and residences.
- Cheap Voltage Change: One advantage of AC is that it is relatively cheap to change the voltage of the current.
- Transmission over Long Distances: AC had the distinct advantage over DC of being able to transmit power over large distances without great loss of energy to resistance.
In contrast, DC is electrical current that flows consistently in one direction. The current that flows in a flashlight or another appliance running on batteries is direct current.
