How to Wire a Solid State Relay?

Solid state relay has reliable operation, long service life, no noise, no spark, no electromagnetic interference, fast switching speed, strong anti-interference ability, small size, impact resistance, anti oscillation, explosion-proof, moisture-proof, corrosion resistance, compatibility with TTL, DTL, HTL and other logic circuits, and can directly drive large current loads with small control signals.

Solid state relay has been widely used in computer peripheral interface device, electric furnace heating constant temperature system, CNC machinery, remote control system, industrial automation device, signal lamp, scintillator, lighting stage lighting control system, instruments and meters, medical equipment, copier, automatic washing machine, automatic fire control, security system, As well as power grid power factor compensation power capacitor switch and so on, in addition in chemical, coal and other need explosion-proof, moisture-proof, anti-corrosion occasions are widely used. In the following, will introduce something about wiring of solid state relay SSR.

Solid state relay is a contactless switch composed of power electronic power device and microelectronic circuit. The isolation device is used to realize the isolation between the control terminal and the load terminal. The input end of the solid state relay uses a small control signal to drive the high current load over zero. SSR relay as the latest contactless switch, perfect replacement AC contactor. Single-phase SSR is a four-terminal active device, including two input control terminals and two output terminals. The input and output are separated by optical isolation. When DC or pulse signal is added to a certain current value, the output terminal can change from off state to on state.

For example, a 40A SSR solid state relay with 3-32V DC control voltage and 24-480V AC load voltage. The protective cover is removed to reveal four terminals. 3 and 4 are control terminals, 1 and 2 are output terminals, and a red indicator light. After wiring is completed, press the button to connect the solid state relay, the indicator light is on, and the solid state relay runs normally. If the switching current of relay exceeds 10A, relay heating will increase. Therefore, heat conduction grease can be coated on the back of the solid state relay, and then heat dissipation can be added. You can watch the video below to learn more about solid state relay wiring.