A solid-state relay (SSR) is an electronic switching device that controls a high-power circuit using a low-power signal. Unlike traditional electromechanical relays, SSRs have no moving parts, which makes them more reliable and faster. They use semiconductor devices, such as transistors or thyristors, to switch the load on and off, providing a longer lifespan and reduced wear. SSRs are commonly used in various applications, including industrial automation, temperature control, and lighting systems. They can handle high voltages and currents while providing electrical isolation between the control and load circuits. This makes them ideal for safely managing power in sensitive electronic systems.