Electrical IBEW Practice Test 2026 - Free IBEW Practice Questions and Study Guide

The primary function of a relay in an electrical circuit is to control a high-power circuit with a low-power signal. This is achieved through the use of electromagnetic principles. When a low-power signal is applied to the relay's coil, it creates a magnetic field that activates a switching mechanism, allowing the relay to open or close a much larger circuit. This capability of a relay makes it valuable in applications where it is necessary to isolate or control high voltage or high current loads safely using a low voltage or lower current control signal.

Relays are used extensively in automation, automotive applications, and industrial control systems due to this ability to handle high-power loads while maintaining control with low-power inputs. This functionality is crucial for protecting sensitive components from high currents and voltages, ensuring safety and efficiency in electrical circuits.