Connecting pH electrode silver wire to circuit

Thread Starter

Materia Dura

Joined Sep 27, 2019
2
Hi Guys,

I'm in the process of making a pH electrode. I've already blown the glass membrane, and have my solutions ready, and my Ag/Cl wire also ready.
I've seen a couple of schematics on the web regarding the construction of the circuit, with different OpAmps and will be trying those soon.

My current concern is with how to connect the silver/chloride electrode wires to the circuit. Can I solder it with a run-of-the.mill flux to a copper-based wire, for example?

Also, some suggest that the connection from the electrodes to the circuit should be made over a co-axial cable, as this is good for low noise, does anyone can give me some direction on how to assemble this.

Many thanks for the input.

Best!
 

jpanhalt

Joined Jan 18, 2008
7,927
Welcome to AAC

1) Silver plating used on a PCB can be soldered with ordinary techniques. You should be OK.
https://www.gabrian.com/5-types-of-pcb-surface-finishes-is-one-of-them-right-for-your-project/

2) With coax cables, the inner electrode is generally the signal and the outer shield is a ground or other connection for noise protection. For combined pH electrodes (one probe with both pH and reference cell), I have seen the reference cell connected to the shield and the active electrode to the center wire. If you use a separate reference probe, the electrodes will go to the center wires and the shields to ground.
 
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