What is a Solid State Relay?
"Solid state relay is a type of relay that has no moving mechanical parts and operates using the electrical and optical properties of semiconductors in the switching process and isolation between its input and output."

It is also called solid state relay or ssr for short in industrial environments. Just like with normal relays, high currents can be switched with SSR using very low currents. It has a structure that transmits or cuts energy when an external (AC or DC) voltage is applied to the control terminals.

How does a Solid State Relay work?
Solid state relay has no moving contacts. It does not physically have mechanical contacts that work with a thrust. It works similarly to a mechanical relay, but uses semiconductor switching elements such as SSR, thyristor, triac, diode and transistor. Also, SSR uses optical semiconductor called photocell (LED) to isolate input and output signals. The photocell converts the electrical signals into optical signals and transmits the signals through the gap. Thus, it completely isolates the input and output sections while transmitting signals at high speed.