I'm trying to connect a Solid state relay using Arduino Nano. I have a push button on the circuit when press, turn on a water pump (1.5hp).
I was able to make the circuit and code for the push button to supply DC for the SSR input and on uploading, the SSR internal LED turns on when supply voltage is given from arduino.
But the strange thing is when I connect the main line to AC in of the SSR I checked the continuity from both terminals, it says no continuity at all. But for some reason I tested the other terminal using a Tester as in the below picture it turns on which means there is current flowing from 1 to 2 without DC input. But why no continuity even then? Also when input DC given nothing happens on AC out terminal..
What I did wrong or Relay is damaged??
Best Answer
You cannot test a solid state relay with Multi-meter. these devices require a minimum amount of voltage/current across the input before the output device will conduct. Most multimeters are designed to simply provide a small amount of voltage in order to measure the ensuing current draw. Therefore, when measuring a solid-state device, the meter will typically report an open circuit (or very high impedance) because it cannot put out enough to turn on the relay.
Please follow this link for more details
the image below is the schematic of an solid state relay. The triac in the solid state relay is going to turn-on and off when there is supply and load connected across it. then only the driver will work.
In order to keep the traic in on-state after gate trigger there needs to be minimum holding current to be present.
Image source: https://www.galco.com/comp/prod/relay.htm
this is due to leakage currents.