Plain English Meaning
The device on the engine that makes electricity while the engine is running. It powers the airplane's electrical equipment and keeps the battery charged.
Full Definition
An engine-driven electrical generator that produces alternating current (AC), which is then rectified to direct current (DC) by built-in diodes to supply the aircraft's electrical system and charge the battery. Alternators produce useful current at lower engine RPM than equivalent generators and are the standard charging source on most modern piston aircraft.
Context Anchor
Seen in aircraft electrical system descriptions, cockpit charging checks, and .