[time-nuts] Lead acid battery noise levels

[Robert Atkinson]

I'd guess that NiMH cells would be similar to Nicads. Cadmium has been banned in the EU, except where it is essential. The power tool manufacturers successfully negotiated an exemption, so they are still available. 
I did note that the paper only considered Johnson and shot noise. The very low frequency noise caused by electrochemical / electrolyte movement was not addressed.

Robert G8RPI.




________________________________
 From: David Kirkby <david.kirkby at onetel.net>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com> 
Sent: Thursday, 11 July 2013, 15:25
Subject: Re: [time-nuts] Lead acid battery noise levels
 

On 11 July 2013 05:47, Mark Spencer <mspencer12345 at yahoo.ca> wrote:
> Eric:
>
>  http://tf.nist.gov/general/pdf/1133.pdf
>
> discusses the noise levels of various batteries.
>
> Regards
> Mark S


Sod's Law comes into play here. From a quick read of that, it seems
NiCd are best, but they are being phased out. I was told they were
banned in Europe, but I don't know if that is true. I'm pretty sure
I've seen NiCd tools in the local DIY store, so I doubt it is true.

Dave
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