Plain English Meaning

Electricity that flows back and forth in a repeating pattern, instead of flowing steadily in one direction. Some aircraft instruments need this kind of power to work.

Full Definition

An electric current that periodically reverses direction, with voltage and current rising and falling in a regular cycle. In aircraft electrical systems, A.C. is typically generated by an alternator or produced from D.C. through an inverter, and is used to power instruments and equipment that require it, such as certain gyroscopic instruments and avionics.

Context Anchor

Seen in aircraft electrical system descriptions, especially when explaining how electrically powered gyroscopic instruments receive power.