What is the role of a relay in an electrical system?

The role of a relay in an electrical system primarily revolves around the ability to control a higher power circuit using a low-power signal. Relays are electromechanical switches that open and close circuits electronically or electromechanically. They are designed to use a smaller current to control a larger current, which permits safe handling and separation of different voltage levels within an electrical system.

When a low-power signal is applied to the relay’s coil, it creates a magnetic field that pulls in an armature, thereby opening or closing the contact points in the high-power circuit. This function is crucial in applications where safety and operational efficiency require the separation of control and power circuits, preventing high voltage from affecting sensitive components.

The other options do not accurately represent the primary function of a relay: reducing voltage levels pertains more to devices like transformers or voltage regulators; measuring electrical current is the role of ammeters or current sensors; and directly powering electrical devices usually involves power supplies or direct connections rather than utilizing relays, which serve as intermediaries in controlling power.