Solid state relay is a series of hibryd that serves as a mechanical relay. Solid state relays is built with insulating an MOC to separate the input and the switch. Solid state relay with us to avoid the occurrence of sparks as it does on conventional relays can also avoid the occurrence of the connection is not perfect because the porous contactor as in conventional relays. Solid state relay circuit is quite simple and we can make in a PCB hole. For more details can be seen in the picture following a series of solid state relays.
Solid state relay has many advantages including no mechanical friction on the contactor, the connection process only occur when there are crosses zero, there is no spark at the contactor, not noisy, small consumtion flow control, better endurance.