[volt-nuts] How long can standard cells last?

[Ed Palmer]

The best reference I've found for standard cells is NBS Monograph 84:  
Standard Cells - Their Construction, Maintenance, and Characteristics.

http://digicoll.manoa.hawaii.edu/techreports/PDF/NBS84.pdf

Ed


On 11/30/2012 6:00 AM, volt-nuts-request at febo.com wrote:
> Subject:
> [volt-nuts] How long can standard cells last?
> From:
> ed breya <eb at telight.com>
> Date:
> 11/29/2012 10:00 PM
>
> To:
> volt-nuts at febo.com
>
>
> I just junked out a very beat up old Fluke 803 differential voltmeter, 
> and found deep within, an old-school Cd/Hg standard cell. It was well 
> protected in an aluminum box, and wrapped in foam and foil. It looks 
> brand-new, and still measures around 1.018... V. I'd like to keep this 
> one as another reference point if it's still good. I assume that it 
> just wasn't used much, or that the Fluke circuits were very good at 
> not loading it down.
>
> I'm sure it is the original unit installed in the instrument - marked 
> 5/12/1960. It is a Muirhead D-845-C. There's no test voltage tag or 
> any other info but a serial number.
>
> So, I'm wondering if a 52 year old standard cell can still be OK, and 
> if anyone knows the specs on these, or where to find the info. I don't 
> know if it's possible, but I'd like to find what the official voltage 
> was supposed to be to a few more digits resolution. I think various 
> types and brands each had slightly different nominal voltages around 
> that determined by the basic chemistry. I remember in the old days, 
> every one I saw included a sticker with the 25 deg C exact voltage 
> measured as accurately as possible back then against the NBS. I'd like 
> to especially know if this is a saturated or unsaturated cell type.
>
> Ed