What is the typical function of a relay in electrical systems?

The typical function of a relay in electrical systems is to switch circuits on and off. Relays are electromechanical devices that use an electromagnetic mechanism to control the opening and closing of contacts in an electrical circuit. When a small input current passes through a coil within the relay, it generates a magnetic field that pulls a lever or armature, which in turn changes the state of the contacts. This allows relays to control a larger circuit with a smaller input signal, making them essential for applications where remote control of devices or automated systems is required. Relays are commonly used for tasks such as activating lights, motors, or other electrical equipment when a particular condition is met.

Other options like limiting voltage, amplifying signals, or measuring resistance are functions of different components or systems, but they do not describe the primary role of relays. For instance, voltage limiting is often accomplished using devices like voltage regulators or fuses, while signal amplification is typically the function of amplifiers, and measuring resistance is done using ohmmeters or multimeters.