Electronics > Metrology

our new product - 5V temperature compensated voltage reference

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fcb:
Hi Mendip,

Hmm. Not quite sure what's going on. Let me know how you get on with another test.  In the meantime (if your happy), let me ship out another unit.


--- Quote from: mendip_discovery on July 17, 2021, 07:24:51 pm ---So I took it to work and tested it on my trusty Agilent @20°C I got a reading of 5.00050V and -5.00051V, taking it further I put the Agilent onto the Transmille and got 5.00000V both ways. I did this during my lunch break but so far I would say its about 100ppm not 10ppm out.

--- End quote ---
So it gave two different readings on the Agilent? And it was spot on with the Transmille? Re-read - now makes sense.


--- Quote from: mendip_discovery on July 17, 2021, 07:24:51 pm ---I dug out the cert that I got with the 5V reference and it irritatingly gives me a measured value of 4.99995 to 5.00005 and no Unc so I can't check my EN ratio so if one of us has an issue. Though I am not worried about the work kit, did a check with UKAS a month ago and they were happy I was well within my Unc.

--- End quote ---
The cal cert we issue is fairly basic (it's a basic product) - we are working on a more data-rich cert (the latest version of EPIC 21.009 allows capturing temperature and voltage measurements during cal). Due to development bottlenecks, this isn't the highest priority we have.

One other thing - it's a 100ppm (0.01%) device, not 10ppm. Our criteria for release is that it the output falls within a +/-10ppm region on our 34465A at several temperature points after cal.  That said your measurements indicate a unit at the extremes.

mendip_discovery:
Don't worry about shipping another just yet.

So 5V on Agilent,


then wires swapped around


Now 5V from Tranny


Wires Reversed. (yeah its not spot on, close enough)


Yup, I get you are working on the cert and I know what its like with very little time to sort bits out. I was hoping with this little unit I could get few tests on it and even at 10ppm I might be able to lend it out to people wanting to do a cal on their personal kit.

mycroft:
The specs (1 year) for 34401A and 34461A for the 10 V range are: 35 ppm of reading plus 5 ppm of range. So 5.0000 V could be read from 4.999775 V to 5.000225 V and the DMM still would be in spec.

For the 34465A the specs (1 year) are 30 ppm plus 4 ppm so the in spec range is 4.999810 V to 5.000190 V.

The values you found are in spec.

mendip_discovery:
I just re-read the advert and it is advertised at 100ppm tolerance, not 10ppm though considering that it is not been on for more than an hour since it was set at 10ppm I would have expected less drift and its at top limit. More time is needed.

FYI here is a graph with the Upper and lower limits of the Spec of the 5V source and the Unc of the Agilent basing FCPs Unc on my own 17025 Unc with error bars. My measurement would say that I am on the middle of being able to say its could be in but it could just as much be way out, this is a thing currently being pushed in labs called Decision Rules. see LAB-48-Decision-Rules-Edition-3-June-2020.pdf

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