[volt-nuts] Calibration and Certification - Trust and detail

[Dr. David Kirkby]

On 12 August 2013 01:58, Charles Steinmetz <csteinmetz at yandex.com> wrote:
> David wrote:
>
>> How useful is this
>>
>> http://www.ebay.com/itm/281149723636 ?
>>
>> On the fact of it, the device would give one a reasonly high
>> confidence something is working readlably well. I wonder if that is
>> good enough for a 3457A.
>
>
> Let's assume that it is still working exactly the same as it was when it was
> calibrated.  The calibration values are recorded to 4-1/2 digits.  So the
> uncertainty is greater than the two LSDs of a 3457A.  Of course, it is
> almost certainly not working exactly the same as it was when it was
> calibrated, which is going to put at least the third LSD of a 3457A in
> question.  So it is good enough for a 3457A only if one is content with a
> 3-1/2 digit verification on a 6-1/2 digit instrument.
>
> Best regards,
>
> Charles

Thank you Charles. Yes, on checking the spec I can see it wont be any use.

Dave