How does an AC generator change the direction of current?

An AC generator changes the direction of current through a slip ring system. This system consists of two conductive rings that are attached to the rotating coil of the generator. As the coil rotates within the magnetic field, it generates an alternating current because the direction of the induced current in the coil reverses every half turn.

In this type of generator, the slip rings maintain electrical contact with fixed brushes while allowing the coil to rotate freely. As the coil reaches the halfway point in its rotation, the direction of the induced voltage and, consequently, the current changes due to the alternating manner of magnetism. The slip rings facilitate a continuous flow of current in the external circuit, providing access to the alternating current that is characteristic of this generator type.

Using a slip ring system is essential for creating AC because it does not interrupt the flow of current during the reversal of direction, unlike other systems such as a split ring, which is typically used in DC generators to ensure current flows in one direction.