What is the main purpose of a relay in electrical systems?

The primary function of a relay in electrical systems is to control a high-power circuit using a low-power signal. This is achieved through an electromechanical mechanism or through solid-state technology where a small electrical current, supplied to the coil of the relay, generates a magnetic field that activates the switch within the relay. This allows the relay to open or close contacts in a separate, high-power circuit, effectively enabling or disabling that circuit without requiring the control signal to handle the high power directly.

This capability makes relays crucial in various applications, such as in automation systems where low-power control signals are used to manage large loads, ensuring safety and efficiency. Using relays allows for more complex control mechanisms while keeping the control side of the system separate from high voltage or high current components, thus providing isolation and added safety.