[volt-nuts] Short term "standard" cell?

[Brooke Clarke]

Hi Chris:

I think it was my Heathkit VTVM that said to get a fresh AA battery and use it as a 1.52 Volt standard to calibrate the 
meter. An even better way was to use a Mercury coin cell since they were 1.35 volts and very stable.  They were used for 
light meters and voltage references because of the very flat discharge curve.

But when you are looking for many more digits of accuracy/precision then a battery may not be the best choice since 
pretty much everything will cause a variation.   Maybe in order of importance: temperature, atmospheric pressure, 
humidity, impedance of measuring equipment, &Etc.

There are a few low cost voltage standards available where the maker has an HP 3458.  For example by Geller and Malone:
http://www.prc68.com/I/MTE.shtml#DCVR

The care and feeding of chemical standard cells is such a pain and they are inferior to the modern electronic standards 
so they have become obsolete.  The label on my Eppley shows 5 digits (4 printed and the last hand written).  Note since 
there's liquid involved there is also an "Up" direction.
http://www.prc68.com/I/Eppley.html#Standard_Cell

http://www.prc68.com/I/Fluke332B.html

-- 
Have Fun,

Brooke Clarke, N6GCE
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

-------- Original Message --------
> In preparation of (hopefully!) Getting that fluke 332A running and sticker shock of what the 732A and similar references go for, I wonder about normal, every day alkaline or lithium batteries and their short term stability.
> Here's the half baked idea.  A fresh, standard 1.5V, or 3V lithium, alkaline, or silver oxide button cell battery, or even an AA sized cell, measured by someone/some place with a known accurate precision meter.  Invisioning 6 or so decimal places.  Could that cell then be shipped, and used as a reference in another altitude?  I haven't spent a ton of time looking, but haven't yet found anything on the web about stability of these types of batteries.
> Regards, Chris
>
>
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