What is relay meaning?

A relay is an electrical switch that opens and closes circuits electronically or electromechanically. It is commonly used in electrical and electronic circuits to perform various functions, such as controlling high-voltage power circuits, switching large currents, controlling motors, and activating alarms. Relays work by using a solenoid coil to energize a set of contacts, which can then either make or break a circuit connection. They are often used in industrial automation, HVAC systems, telecommunications, and automotive applications. Some of the common types of relays include electromagnetic relays, solid-state relays, thermal relays, and reed relays.