[volt-nuts] LTZ1000 project build

Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby at kirkbymicrowave.co.uk
Wed May 25 17:06:02 EDT 2016

On 25 May 2016 at 19:24, Russ Ramirez <russ.ramirez at gmail.com> wrote:

> A lot of great information Eric, thanks for sharing the link.
> Due to my ignorance in general on the subject of Metrology, I have the
> following question for the list.
> If one built a project with the LTZ1000, like the one described on xDevs
> and could set it to a value of 7.15000000v at the NIST lab, and observed
> stability to 7 1/2 digits, would using that device to calibrate your own 7
> 1/2 digit DMM be considered NIST traceable? Let's say your device is well
> insulated and battery powered, and your calibration was done at the same
> altitude and room temperature as at NIST, plus anything I left out that
> would make the conditions ideal.
> The above was not meant to be a trick question, and I may have asked it
> incorrectly, but I view the answers as instructive - or I hope they are.
> Russ

As far as I can determine, as long as you can work out the uncertainties,
no matter how large they might b,  the measurement is traceable. If you use
a 3.5 digit multimeter that is NIST traceable to calibrate a 7.5 digit
multimeter, the calibration is still NIST traceable. The calibration will
be pretty useless, and you may not be accredited, but it is still NIST

Or if you want to be accredited, get your mate down the local pub (bar) to
accredit you!

On a more serious note, if people felt that design was good, and wanted to
produce the PCBs. and/or make parts available, I'd be interested. I only
have a 6.5 digit meter, but feel sure I could find someone with a 3458A in
the UK who could measure the voltage for me.

Dave <not a metrologist>

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