02-21-2008, 11:16 AM
Join Date: Apr 2005
Location: Sacramento, CA, USA
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| | Re: DIY Electronic pH Indicator
The pH probe doesn't produce any voltage itself, as I understand it. Instead it modifies the voltage applied to it. It is that change in voltage that the meter reads. (I could easily be wrong, but that's what it looks like.) Also, I just realized that you need a temperature reference for this to work accurately. There is probably an easy way to do that, but I don't know what it is.