Alternating Current (AC)

Alternating current (AC) is an electric 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 homes and businesses — it is what flows when you plug an appliance into a wall outlet. The frequency at which AC reverses direction is 60 Hz in North America (50 Hz in most of Europe).

In This Home

All standard wall outlets in the duplex supply AC power. The [APC UPS](50-Devices/Home Network/APC UPS.md) in the lab converts incoming AC to DC to charge its batteries, then back to AC to supply power to connected equipment during an outage.