It has been several decades since I took a physics class, but I seem to remember that the voltage produced by two dissimilar metals in an electrolyte produced a known, constant voltage, independent of the electrolyte. The electrolyte did control internal resistance and current, but not voltage. So, if copper and zinc give a voltage of 1.100 can I cobble a temporary, low current, source accurate to thousandths of a volt? Do I remember the voltage correctly? Thanks

 

No, not accurate to thousandths of a volt very easily. For that you need a calibrator like my old Omega CL511.
https://forum.allaboutcircuits.com/threads/super-moon-shine.100322/#post-899878

https://www.chem.wisc.edu/deptfiles...odules/electrochemistry/05potential/18_51.htm

 

No, not accurate to thousandths of a volt very easily. For that you need a calibrator like my old Omega CL511.
https://forum.allaboutcircuits.com/threads/super-moon-shine.100322/#post-899878

https://www.chem.wisc.edu/deptfiles...odules/electrochemistry/05potential/18_51.htm

 

OK--your second link shows 0.76 for zinc and 0.337 for copper so 1.097. Can I trust that? Or are there variables I don't know about?

I saw your first link some time ago; interesting but far, far, beyond my needs or desires.

Thanks.

 

My chemistry is a little weak on the exact Nernst equation effects of temperatures and concentration but maybe this will give you an idea.

https://pennyroyalresearch.files.wo...ature-and-concentration-on-galvanic-cells.pdf

 

There is also the issue of reagent purity. It wouldn’t be hard to get “close” but if you need precision, you’ll need high purity.

The short answer remains: this is a very tough way to establish a reference.

 

There is also the issue of reagent purity. It wouldn’t be hard to get “close” but if you need precision, you’ll need high purity.

The short answer remains: this is a very tough way to establish a reference.

Correct, a electronic precision voltage reference is a no brainier but thousandths of a volt accuracy can be expensive.
My CL511 voltage spec: