Semiconductor-based switching elements offer two essential advantages compared to electromechanical relays: superb reliability and a nearly limitless lifespan. The various solid-state relay types all function according to the same principle: in the input circuit, an LED energizes an optoelectronic device via an optical beam (insulation method), which in turn activates a power semiconductor on the output. SSR types use a triac as an output power semiconductor.
Applications
Household appliances – Healthcare and medical equipment – Industrial machines