What is the primary function of a relay in an electrical circuit?

The primary function of a relay in an electrical circuit is to open and close electrical contacts. A relay acts as an electromechanical switch that allows a low-power signal to control a higher power circuit, which is essential in various applications such as automation, switching, and protection.

When an electrical current flows through the coil of the relay, it creates a magnetic field that moves the armature, either opening or closing the contacts. This mechanism enables the relay to control larger currents or voltages without requiring direct physical interaction.

Utilizing relays ensures safe operation by allowing control circuits to work at lower voltages, while still managing more hazardous or higher power loads effectively. This function is vital in many systems, such as aircraft control systems, where safety and reliability are paramount.

In contrast, amplifying current does not fall within the functionality of a relay, as relays don't increase current levels. Similarly, measuring voltage is more accurately accomplished with voltmeters, while preventing short circuits involves protective devices like fuses or circuit breakers rather than relays.