How does a relay function in an electrical circuit?

A relay functions as an electrical switch that uses a low power signal to control a higher power circuit. This mechanism is key in many electrical applications, allowing a small control signal—typically from a low-voltage source—to activate a much larger load, which may operate at higher voltages and currents.

The relay contains an electromagnet that, when energized by the low power signal, creates a magnetic field that moves a physical arm to either make or break a connection in the higher power circuit. This allows the relay to control electronic devices safely, providing isolation between the control circuit and the load while enabling the operation of high-power equipment without requiring a direct connection.

Understanding this function of relays is crucial in various applications, such as motor control, automation systems, and safety circuits where controlling higher voltages from a safer, lower-voltage system is necessary. This relationship underscores the importance of relays in enhancing the versatility and safety of electrical systems.