[time-nuts] quartz thermometers

ken hartman ken at hartmans.org
Sat Mar 12 04:21:24 EST 2016


Interestingly, the use of AC-cut crystals (high linear tempco of frequency)
is found in the development of OCXOs. Using a reference AC-cut resonator -
in place of the final AT/SC resonator - one can learn much about the
thermal  characteristics of the oven loop performance. While not a precise
temp sensor, it is a high sensitivity  indicator of  temperature variations
of the resonator.

On Fri, Mar 11, 2016 at 11:44 PM, Bill Hawkins <bill.iaxs at pobox.com> wrote:

> It may be that the need for that kind of resolution died out.
>
> The next step up from quartz thermometry is resistance thermometry.
> The linearization equation for platinum has enough terms to make it
> uncertain around .01 C.
> Temperature calibration baths usually use platinum resistance sensors.
>
> It may be that the triple point of water does not have the certainty to
> reach '0.0001C'
>
> Disclaimer: I only worked with industrial sensors from Rosemount, Inc.
> as an employee.
>
> Bill Hawkins
>
>
> -----Original Message-----
> From: Alan Ambrose
> Sent: Friday, March 11, 2016 11:42 AM
>
> Hi,
>
> I hope this is still relevant and not too off-topic...but since it
> involves crystals and tempco...
>
> Quartz thermometers (e.g. the HP 2804A) with their 'linear cut' crystals
> and '0.0001C resolution' seem to have been a thing from the mid-60's to
> the mid-80's:
>
> http://www.hparchive.com/Journals/HPJ-1965-03.pdf
>
> There still appear to be some manufacturers making the crystals:
>
> http://www.statek.com/products/pdf/Temp%20Sensor%2010162%20Rev%20B.pdf
>
> Anyone know why they died out? Did a better technology replace them?
>
> TIA, Alan
>
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