What role does a relay play in an electrical system?

The function of a relay in an electrical system is to act as a switch that operates on a low power signal. This capability allows a relay to control a larger current circuit through a smaller current circuit. Essentially, when a low voltage signal is applied to the relay, it energizes an electromagnet, which then closes or opens the switch within the relay, enabling or disabling the flow of electricity in the larger circuit.

This attribute makes relays particularly useful for applications where a direct connection to a high-power circuit is impractical or hazardous, providing both safety and control in various automation and switching applications. The ability to operate on lower power signals means that relays can be easily integrated into modern control systems, where they can respond to sensors, timers, or other low-power control devices.

In contrast, measuring voltage levels, acting as a fuse, or regulating the flow of electricity are distinct functions not served by relays. Measurement typically requires other instruments like voltmeters, fuses are sacrificial devices designed to protect circuits from excess current, and regulation is often handled by devices such as transformers or voltage regulators. Thus, the correct role of a relay focuses on its switching functionality driven by low power signals.