What does a relay do in an electrical circuit?

A relay functions as an electromechanical switch in an electrical circuit. Its primary role is to control the flow of electricity through one circuit by using a low-power signal or by different electrical power sources. This allows a relay to manage larger loads without requiring direct interaction between the control circuit and the high-power circuit.

When a voltage is applied to the relay's coil, it creates a magnetic field that moves a lever or armature, which then opens or closes contacts. This action completes or breaks a connection in another circuit. By doing so, a relay can activate or deactivate devices such as motors, lights, or other components based on a relatively small input signal, making it an essential component in many automated systems and control panels.

This capability of relays underscores their significance in electrical engineering and automation, enabling the design of safer and more efficient circuits that can control high-power devices with low-power signals.