[time-nuts] HP5065A C-field current is temperature sensitive

Poul-Henning Kamp phk at phk.freebsd.dk
Mon Aug 31 02:32:54 EDT 2015

In message <A1A54F1F-926F-42A9-8AEC-F83BCAF4E58D at n1k.org>, Bob Camp writes:

>As we go joyously bashing the poor guys that designed this beast,
>it’s worth noting just how old the design is. 741 op amps were
>indeed “modern” [...]

I don't think chip op-amps appear until the 5065 is a toddler, later
revs use a couple of them.

The only thing I feel like beating them up about, is that appearantly
they didn't consider the tempco of the R10||R11 pair (or maybe it is
just R10 - not sure yet).

Either way:  If any of you have a non-amazing HP5065, Measure the
A15CR5 voltage, multiply it by 76, and replace R10||R11 with something
of that value and better than 5PPM tempco.

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.

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