At its core, relay technology refers to the use of devices called relays to control electrical circuits. A relay is an electrically operated switch that allows low-power signals to control high-power circuits. It works by using an electromagnet to operate a set of contacts, either closing or opening them to control the flow of current in a circuit. This basic mechanism has been adapted in various forms for diverse applications, from controlling motors in machinery to managing network traffic in communication systems.

    There are two primary types of relays： mechanical relays and solid-state relays (SSRs).