[volt-nuts] volt-nuts Digest, Vol 33, Issue 6

[Demian Martin]

AC Volt-nuttery has its limits and challenges. I now have 3 Fluke 540B's,
6-8 Thermal converters, an assortment of AC meters culminating in a Fluke
8506A as well as an Optimation AC calibrator, a Tek 191 scope calibrator and
other AC sources for calibration. Even after getting the 8506A calibrated
I'm not sure what I can trust. It's much easier to get resolution than
accuracy for AC. Even NIST has really clear limits on what they can have
confidence with.  On the Ratiotran's there are frequency limits. But you can
search and maybe find a HF ratiotran (I found one). There is an obscure
capacitance meter that uses a ratiotran to get PPM accuracy on cap values.

Fortunately for us these old instruments are relatively cheap given that
they still are the state of the art.

Unfortunately in this category moving the excess on (I do not need 3 540B's)
is very difficult. I have even looked for a local museum to donate my older
stuff (measurement standards back to the 50's) and found no takers.
     Demian


Date: Tue, 08 May 2012 19:32:05 +0000
From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
To: volt-nuts at febo.com
Subject: [volt-nuts] AC volt-nuttery...
Message-ID: <82017.1336505525 at critter.freebsd.dk>
Content-Type: text/plain; charset=ISO-8859-1


For reasons which you would probably recognize, I ended up buying a Dekatran
DT72A because it was simply too cheap to let go.

That is a pretty amazing instrument.  Appearantly the only thing Tegam
changed in the new B version was the box, shaving a some kilos of the
weight, as far as I can tell, everything else in the manual is identical up
to and including the errors in the final schematic.

I find somewhat ironic that my HP3458A can measure DC into tenths of PPM,
while I have nothing in my lab that can reliably produce that, whereas it
can only measure AC to tens of PPM, while I now have a fully passive box
which can generate it down to tenths of PPM.

So is volt-nuts DC only, or are anybody playing with AC also ?


-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.


***********************