[volt-nuts] Traveling Standards

[m k]

Date: Fri, 19 Oct 2012 21:34:38 -0500
From: smither at c-c-i.com
To: volt-nuts at febo.com
Subject: Re: [volt-nuts] Traveling Standards

On 10/18/2012 02:05 PM, Andreas Jahn wrote:
> Hello Bob,
> 
> whats the matter with you. Infected by precision virus like me?
 
Yep - and I have a question.  What does the spec of Xppm/sqrt(1,000 hrs) mean?
If we expect Xppm over the first 1,000 hours, does the stability improve with
long term operation?  What would be expected over the second 1000 hours, etc?
 
Would we expect a drift of 1.4 * X ppm over 2000 hours, sqrt(10) * X ppm over
10,000 hours, and so on?



In theory yes, but there are some aspects like continuing corrosion of the 
wirewound resistor wire I suspect that will be closer to linear, 
but if the oxide is very adherent then it may well be root time. a poorly 
adhering film will have steps in its corrosion rate as fragments of oxide etc 
fall off.




Regards,

MK