What role does a relay play in electrical systems?

A relay serves a critical function in electrical systems by acting as an electrically operated switch. It allows a low-power control signal to switch a larger power load on or off without the circuits being directly connected. This capability is vital for protecting sensitive control circuits from high voltages or currents, enabling automation and remote control of electrical devices. The operation of a relay typically involves an electromagnet that, when energized, pulls a switch mechanism to either open or close a circuit, making it a fundamental component in various applications such as control panels, automotive systems, and home automation.

In contrast to other options, measuring voltage levels is a function typically performed by instruments like voltmeters. Reducing power consumption is achieved through design considerations, not directly through a relay's operation. Converting AC to DC is the role of rectifiers, which specifically handle the transformation of electrical current types. Thus, the relay's primary role focuses solely on switching operations within circuits.