[time-nuts] Re: pulling some crystals

[Ed Marciniak]

There are many resistor materials. Some work better than others in certain resistance ranges. Thick film with a ruthenium/niobium oxide in glass, thin film with either NiCr or TaN and platinum(temperature sensors) are four that come to mind.
________________________________
From: glen english LIST <glenlist at cortexrf.com.au>
Sent: Friday, December 8, 2023 9:39:52 PM
To: Ed Marciniak <ed at nb0m.org>; Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
Cc: Bob kb8tq <kb8tq at n1k.org>
Subject: Re: [time-nuts] Re: pulling some crystals

Ed and Ben,  thanks very much for the input.

Yeah I am going to have to look into the aging of the frequency
sensitive parts in the circuit . I've never had to do this before - when
I've built an OCXO, there has always been the expectation that someone
could tweak it once a year per year  if necessary .

Of course, this stuff is not new. Try retweaking your XO out beyond
Saturn ...... My guess is I'll need to tweak the L in the OT oscillator,
so I could switch in L in binary bulk steps maybe (rather than the
traditional tiny ally core slug tuned L I have used) .  Of course there
will be a limit to how far I can go.

There are certainly some DC bias aging effects on high K dielectric
MLCCs. According to  :

https://urldefense.proofpoint.com/v2/url?u=https-3A__www.knowlescapacitors.com_getmedia_0d900fa3-2D87c5-2D4b78-2Daae5-2Dff6a837f1a3a_an0006&d=DwIDaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=JsDsKeR7cZC8wbZhIlxxBQ&m=rbe-1Qm0H4REWicyxpys_ldUubZPIP7OhVUuixQM8Vn-hewmhFKo6IqPX1YK0_1d&s=f7ti6aCVGdc4Mj4fzddVas6FeUzAlbCbJfEVRozArmA&e=

aging on NP0 dielectrics is negligible, but that is at room temperature.
Interesting on the concept of 'resetting the aging process' by bringing
the dielectrics about their Curie Point. (including soldering)

Also, there is diffusion of impurities into the capacitors. Probable
also means I should use thick film resistors.

But by the sounds of it, the crystal will dominate the aging process.

On 9/12/2023 1:09 pm, Ed Marciniak wrote: