solid sate relay

  • Hi there,
    Anyone out there experienced with solid state relays?
    I ordered two of those modules:
    4 channel solid state relay

    I wanted to play with them but seems both are broken. When connecting them to the Arduino, only the onboard status LED changes the state but it does not switch. When using a standard relay module, it works well. Ok, maybe this needs more juice, but even having up to 6V and enough AMP does not change anything.
    I measured the voltage on the board and when I trigger the relay, I have 4.4V (via standard 5V input) on the two relay pins, nothing happens.
    Even after putting direct load on the relay, it does not switch. The only explanaition to me: they are all broken. But 8 of them?
    Do I miss anything?

    Is there a difference with classic relays and solid state relays when it comes to triggering?


    PS: I know that there is no clicking sound - measured it with the multimeter 🙂

  • Hero Member

    Yes, they do work and I've a few of these running fine.
    What are you trying to measure with the multimeter? Did you connect a load to the SSR? I suppose a SSR has a high impedance, so maybe you can't measure the impedance, like with a relay.
    Please keep in mind that the logic on a SSR is inverse to the logic of a relay. You have to modify your sketch.

  • @TimO thank you.
    well I just measured if the relay is closed when triggered but it does not close, therefore I assumed it does not work. This has been tested with my continuity multimeter. Just added a lamp and it works. strange thing, need to dig in to understand this.


  • @parachutesj this is the way SSRs work. I do not think you can test them without a load