pH meter/controller prototype
Note that the connection from the pH electrode BNC
connector to the input of the amplifier (yellow arrow) on this prototype is very
short and direct . The reason for this is that this is an extremely high impedance
point, and any extra wire length here will act as a very effective antenna,
picking up any electrical noise in the area.
Photo of a pH controller built by a reader
When completed, this circuit reportedly
worked fine, despite the fact that it was made by an inexperienced builder, on perf
board, and with very long leads.
A pH meter adapted from the circuit described here,
enhanced with a microcontroller, analog to digital converter, and additional circuitry.
(Click image to view full size.)
More pH-related photos are available at The pH Pages.