What is the primary purpose of a relay in a circuit?

The primary purpose of a relay in a circuit is to switch the control circuit. A relay functions as an electrically operated switch that allows the control of a larger circuit using a smaller input signal. When the control circuit applies voltage to the relay's coil, it generates an electromagnetic field that moves a switch mechanism, thus opening or closing the circuit it controls. This makes relays incredibly useful for controlling high-power devices with a low-power signal, enabling effective remote control and automation in various applications.

In addition, relays are often used for their ability to provide isolation between different circuit components, but their main function is to act as a switch. Although amplifying signals or storing electrical energy are important in other contexts, they do not represent the fundamental role of a relay. Understanding the switching capability of relays is crucial for anyone working with electrical systems and automation.