What is the primary role of a relay in electrical circuits?

The primary role of a relay in electrical circuits is to enable a low-power signal to control a high-power circuit. Relays operate as electrically operated switches; they consist of an electromagnet that, when energized by a small current, creates a magnetic field. This magnetic field pulls a lever that opens or closes the switch contacts, allowing or interrupting the flow of a larger current in the power circuit.

This functionality is crucial in various applications where direct control of high-power circuits is not feasible due to safety or logistical concerns. By using a relay, it's possible to safely control larger loads such as motors, lights, or heating systems from a low-power control circuit without exposing sensitive components to high voltage or current.

The other options reflect different functions that are not the primary purpose of a relay. For instance, amplifying signals is characteristic of amplifiers rather than relays. Automatic disconnection is more related to circuit breakers which provide safety by disconnecting power under fault conditions. Voltage regulation is a function typically associated with voltage regulators, ensuring that a consistent voltage is supplied to electrical loads.