What is the main function of a relay in an electrical system?

The main function of a relay in an electrical system is to control a circuit by using an electrical signal to operate a switch. Relays are electromagnetic devices that use a low-power input signal to control a larger power circuit. When the relay is energized by an electrical signal, it creates a magnetic field that moves a mechanical armature, allowing it to either open or close the contacts within the relay. This allows the relay to control the flow of electricity in the circuit without the need for a direct human operation of the switch, enhancing safety and automation in electrical systems.

While amplifying signals, measuring resistance, and converting AC to DC are important functions in other electrical components and systems, they do not represent the primary purpose of a relay. Relays are specifically designed to act as a switch controlled by an electrical input, making them vital for applications where remote control or automated switching is necessary.