Re: ELECTRO-CHEMICAL ELAPSED TIME INDICATORS

On Sat, 14 Dec 2024 14:29:38 -0500, Joe Gwinn <joegwinn@comcast.net>
wrote:

There was a question (from Larkin?) on non-electronic time delay
components, and I recalled such a thing from the 1970s, when I
considered using it to sequence an electromechanical gadget.  Turned
out to bet too complicated in that application, and went to a CMOS
counter.
>
Anyway, the name came to me today, and it is still made.
>
Curtis coulometers are analog Elapsed Time Indicators (ETIs) which use
an electro-chemical plating process to integrate current over time.
>
.<www.curtisinstruments.com>
>
.<https://lampes-et-tubes.info/uv/Curtis_coulometers.pdf>
>
This uses mercury, but if I recall correctly, the 1970s original used
silver.  I think it was called a coulcell.  The original company seems
to be gone.
>
Joe Gwinn

The first residential electric meters, in the Edison DC days, were
electrochemical. I think they weighed something to set the bill.