A relay switch controls high-power circuits using low-power signals by utilizing an electromagnet to mechanically switch the contacts in the circuit. When a low-power signal is applied to the relay coil, it creates a magnetic field that attracts or repels the switch, causing it to open or close the contacts for the high-power circuit. This allows the relay to isolate the low-power control signal from the high-power circuit, providing a safe and reliable way to control high-power devices with low-power signals.
