[time-nuts] HP5065A C-field current is temperature sensitive
Poul-Henning Kamp
phk at phk.freebsd.dk
Sat Aug 29 15:33:11 EDT 2015
--------
In message <8BE4F2B1-171B-4117-88A5-A6DC64D9890D at n1k.org>, Bob Camp writes:
>Most potentiometers have very good TC when used in a “ratio mode”.
>You can quickly mess that up by putting resistance in series with
>the pot. It’s a bit surprising how may times you see this inherent stability
>messed up that way.
Yes, but they do have a good reason for it here: They want the
C-field pot to be "calibrated" in frequency so they need the
resulting voltage to follow the quadratic C-field sensitivity
decently well.
I still havn't figured out what component is responsible for the
huge tempco, but it is not the C-field pot. There's a few PPM
there but not that many.
--
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.
More information about the time-nuts
mailing list