What component is used in slip rings to connect the armature to the induced voltage?

In a slip ring assembly, brushes are the components that make contact with the slip rings to facilitate the transfer of induced voltage from the rotating armature to the external circuit. The slip rings are conductive rings mounted on the rotor, allowing the armature to spin while maintaining an electrical connection.

When the rotor turns, the brushes press against the slip rings, ensuring that the electrical current generated in the armature's windings can be continuously and effectively delivered to the external circuit without interruption. This is critical in applications such as electric motors and generators, where the induced voltage needs to be accessed while the rotor is in motion.

Wires are not directly part of the slip ring assembly, as they serve a different purpose in transmitting current over distances. Contacts can refer to various electrical connections but do not specifically denote the mechanism for transferring voltage in this context. Transformers, on the other hand, are devices used to change voltage levels in alternating current circuits and are not directly involved with the functionality of slip rings.

Thus, brushes are essential in ensuring uninterrupted electrical connectivity between the rotating and stationary components, making them the correct answer.