I recently bought a CKRD2420 relay. I connected the required control voltage and then connected 120 VAC to the input of the load side. I stuck one prong of my voltage meter in the load output of the relay and the other prong to ground. As soon as the load side was energized the output load was also energized. It did not matter whether the control voltage was high or low. I chatted with a digi tech who said that the relay was probably bad. So, I ordered two more (one credited by digikey). I tested them when they arrived and they both performed identically to the first one. Am I missing something?
That solid state relay has more than enough leakage current (10mA) to cause a reading on a volt meter when the relay is off.
To check it with a multi-meter, add a load (e.g. lamp) to the output and connect the volt meter across the load. The leakage current is absorbed by the load allowing the volt meter to indicate the on/off states.
Depending on the circuitry of a specific ohm meter, it may be possible to measure a resistance change on the output when the line voltage is not connected to the output.
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Thanks, Paul! I connected the relay output to a process and it worked as intended. A great learning experience for me! Thanks again for your reply.
On a tangential note, that same leakage current that makes unloaded function testing difficult on an SSR also presents a potential shock hazard. Safety-related disconnects tend to be of a mechanical sort for this reason.
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