What is the purpose of a relay in electrical circuits?

The purpose of a relay in electrical circuits is to allow a low-power circuit to control a high-power circuit. This is achieved through an electromagnetic mechanism, where the low-power signal activates the relay, which in turn completes the circuit for the high-power load. This design provides several benefits: it isolates the low-power and high-power circuits, enhancing safety; it allows for the control of large electrical devices using relatively small inputs; and it enables automation in systems where switches may not be conveniently placed.

A relay serves as an intermediary that can handle higher voltages and currents without exposing control equipment to the risks associated with those higher power levels. This capability is particularly useful in applications where remote switching or automation is needed. Understanding this function helps in recognizing how relays contribute to the design and operational integrity of electrical systems.