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Solid State Relay Question


so I know there has been posts before about solid state relays being used to control solenoid valve, I have attached a picture of the diagram I found on the forum that Peter did for wiring a solid state dc relay.

I have also attached a picture of the solenoid valve I want to control with the relay. How do I wire this into the circuit for the solid state relay, the solenoid I have only needs +- dc power to be operated.

I have attached another quick hand sketch of how I interpret the wiring is this correct, if so it means the + power goes through one side of the solenoid coil and out of the other side? Is that correct?

thanks in advance



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Your sketch looks correct

The coil can be wired up in either direction, however your solenoid coil has an LED in parallel to the coil (this will only light if the power is applied in the correct direction).

If one of the solenoid terminals is marked positive - it should be connected to the power supply positive terminal.

Make sure that your solid state relay output is rated for DC voltages. There are AC solid state relays (SCR/TRIAC) that once turned on don't turn off until the current goes to zero (which happens 100 or 120 times a second for AC circuits).

Wow thanks for the quick reply.

i have attached a picture of the solid state relays I intend to use.

ok so if one side of solenoid is marked + then put positive power in that side and then back out of other side into relay output 2?


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@MiniMillAidan - time zones were working in your favor.

Did a bit of research on solenoid valve connectors (formally known as DIN 43650 connector). The solenoid valves typically have 3 terminals which are labelled 1, 2 & E. Apparently the industry convention is terminal 1 is hot/positive, terminal 2 is cold/negative and terminal E is the body of the valve. The LEDs of these connectors are typically bipolar meaning they will glow if power is applied to terminals 1 & 2 in either direction.

Recommended wiring:

  • Connect power supply positive to terminal 1 of solenoid
  • Connect terminal 2 of solenoid to terminal 2 of solid state relay
  • Connect terminal 1 of of solid state relay to power supply negative

If the E terminal is connected to anything it should be the earth wire from the wall plug. The reason it exists is that some solenoids use mains voltage, should the solenoid winding short out with the solenoid body it could make the entire solenoid be at mains voltage (electrical shock hazard) and therefore the earth connection is to provide a safe conduction path (typically blowing a fuse in the process).