This document describes an alternating current (AC) generator. It begins by defining an AC generator as a device that converts mechanical energy into electrical energy by forcing electric current to flow through an external circuit. The document then discusses the key parts of an AC generator, including its coil, magnetic field created by magnets, slip rings, and brushes. It explains that an AC generator works on the principle of electromagnetic induction, where changing magnetic flux within its coil induces an alternating electric current. The document provides diagrams and describes how rotation of the coil between magnetic poles produces this changing flux and the alternating current output. Finally, it outlines some common applications of AC generators like in vehicles, appliances, and power distribution grids.