[volt-nuts] Resistance standard
rob.klein at smalldesign.nl
Mon Aug 22 12:06:14 UTC 2011
Now why do I never make such a 'find'? ;-) You are right that the
Z-foils are (supposedly) much more stable than the 742A, which is
exactly what started me on my quest.
I did receive those VHP202Z's in late March last year and did some very
brief testing on them. However, what with getting married,
becoming father to a son and having major work done on the house and
incidentally having to run my business as well, I'm afraid
I've had to curb my nuttery since then. Also, the arrival of two Fluke
5440B's in need of some TLC has taken up quite a bit of time.
So, overall, not much progress on the standard front. Until, that is, I
happened upon an ESI SR104, last week! That, in itself is of course
all the standard I would ever require and so there is no real need to
roll my own any more. Still, I wouldn't be much of a nut if I'd let
that stop me. Now, at least, I have the penultimate standard to compare
my home-brew against.
Op 22-7-2011 22:24, Robert Atkinson schreef:
> Hi Rob,
> How is the standard going?
> I've had renewed interest as I just "found" a pair of 200 ohm VHA516-6 Vishay Z foils in a scrap biotech unit that came in an auction lot. Reviewing the thread I revisited the Fluke 742A comparison. While the VHAs are not as "accurate" as the 742A (50ppm for the 200R) They are MUCH more stable at the 720A power levels, 2 ppm for 6 years compared to 6ppm at 1 year for the Fluke. So they should make a grat transfer standard.
> Robert G8RPI.
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