[time-nuts] cheap USB voltage sensor

Don Latham djl at montana.com
Fri Jan 13 16:27:02 EST 2012


Right, Poul! And I've found, by lots of headbanging on walls,
GROUNDLOOPS!!!!! even at 12 bits...
Don

Poul-Henning Kamp
> In message <20120113200200.14805.qmail at s421.sureserver.com>,
> "=?iso-8859-1?Q?be
> ale?=" writes:
>
>>I have some and they work well. Here's a plot of voltage vs time
>>on an AA battery, showing the 18 bit performance (1 LSB = 15 uV).
>>Noise is generally +/-1 LSB.
>>https://picasaweb.google.com/lh/photo/q7Lq4oAX_0347S8BO0eHSA
>
> Did you try to hold the battery in your hand while you did that ?  :-)
>
> Be aware that once you get to approx microvolt, you have to take
> into account things like the temperature difference between plug and
> socket because the thermoelectric effect kicks in.
>
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by
> incompetence.
>
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-- 
"Neither the voice of authority nor the weight of reason and argument
are as significant as experiment, for thence comes quiet to the mind."
R. Bacon
"If you don't know what it is, don't poke it."
Ghost in the Shell


Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com






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