Short term "standard" cell?
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
Sent from my SMRTphone
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
Sent from my SMRTphone
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On 03/11/2017 11:51 AM, kc9ieq via volt-nuts wrote:
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. Â Here's the half baked idea. Â 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. Â Invisioning 6 or so decimal
places. Â Could that cell then be shipped, and used as a reference in
another altitude? Â 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,
A silver oxide battery might give you a decimal point of long term
stability.
For just a few dollars more you can get a real reference
http://www.voltagestandard.com/
I've had a VREF5-01 for 5 or 6 years now. It continues to read 5.0000
on my 5.5 digit Fluke. I use it to check my portable DVMs.
John
--
John DeArmond
Tellico Plains, Occupied TN
http://www.tnduction.com <-- THE source for induction heaters
http://www.neon-john.com <-- email from here
http://www.johndearmond.com <-- Best damned Blog on the net
PGP key: wwwkeys.pgp.net: BCB68D77
How do silver oxide cells compare to mercury cells for voltage
stability? When I last looked into this, I concluded that there were
two different silver oxide chemistries with a slight variation in
voltage between them.
On Sat, 11 Mar 2017 09:21:02 -0800, you wrote:
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
Brooke wrote:
There are a few low cost voltage standards available where the maker has
an HP 3458. For example by Geller
Geller has been gone as a supplier since 2013 (most of the web site is
still up as an archive, but he is no longer selling the voltage
"references").
There are a few low-ish cost "references" or "standards" advertised on
ebay. An annotated schematic of one NOT to get (the Calibratory D-105
"2ppm Voltage Reference") can be found here:
Best regards,
Charles