Robo-Tank pH circuit accuracy

[robsworld78]

Depends on the internal wiring I guess. I am using your 12VAC/DC Converter with LM2596 DC/DC step down to 5V. The LM2596 is not isolated completely, so the GND is the same on all my 12V and 5V rails.

The AC/DC Converter has a Earth connection, but only uses that to earth its cage, not to give a defined GND level. I’ll have to earth that using a resistor and capacitor as well, I think.

Yeah I think you're right it probably wouldn't help much. Still a mystery to me why a few have this issue.