[time-nuts] What do people use for meassuring temperature?

[Bruce Griffiths]

Here's a NIST paper on Thermistor stability:
https://ia800609.us.archive.org/2/items/jresv83n3p247/jresv83n3p247_A1b.pdf

Bruce
> On 28 September 2020 at 01:37 John Ponsonby <jebponsonby at gmail.com> wrote:
> 
> 
> Bruce Griffith points to the note put out by Littelfuse. It is very meagre. It says that '...thermistors can be produced with  typical drift of only 0.001˚C to 0.002˚C per Year." It doesn't say that they are produced and still less that Littelfuse produces them. Bruce also refers to thermistors being  'Suitably conditioned at 25˚C' What is this conditioning process and what if the intended working temperature is not 25˚C?. Surely more must be known about this matter.
> Jeremy Nichols' questions are very apposite.
> I see that the Steinhart Hart Equation seems to be entirely empirical without any underlying semiconductor theoretical foundation.
> John Ponsonby
> 
> 
> Do we know what this ?Long Term Aging Process? is or is it proprietary?
> 
> 
> 
> On Sat, Sep 26, 2020 at 5:03 PM Bruce Griffiths <bruce.griffiths at xtra.co.nz <mailto:bruce.griffiths at xtra.co.nz>>
> wrote:
> 
> > Drift ~1-2mK per year for suitably conditioned thermistors at 25C:
> > 
> > 
> > https://www.littelfuse.com/technical-resources/technical-centers/temperature-sensors/thermistor-info/thermistor-terminology/stability.aspx <https://www.littelfuse.com/technical-resources/technical-centers/temperature-sensors/thermistor-info/thermistor-terminology/stability.aspx>
> > 
> > 
> > 
> > Bruce
> > 
> >> On 27 September 2020 at 11:15 Bob kb8tq <kb8tq at n1k.org <mailto:kb8tq at n1k.org>> wrote:
> > 
> >> 
> > 
> >> 
> > 
> >> Hi
> > 
> >> 
> > 
> >> Roughly speaking 99.99999% of all OCXO?s use thermistors as temperature
> > sensors.
> > 
> >> The normal evaluation process on a new one *probably* would catch
> > something < 0.01C
> > 
> >> over a few months. You may do it a couple different ways depending on
> > the target
> > 
> >> OCXO. The net result is still in the ?golly gee wiz low? sort of range.
> > If you can detect a
> > 
> >> drift / shift, you disqualify that part and move on to another one. Very
> > few glass bead
> > 
> >> parts seem to get tossed out ?..
> > 
> >> 
> > 
> >> Bob
> > 
> >> 
> > 
> >> 
> > 
> >> 
> > 
> >>> On Sep 26, 2020, at 4:23 PM, John Ponsonby <jebponsonby at gmail.com <mailto:jebponsonby at gmail.com>>
> > wrote:
> > 
> >>> 
> > 
> >>> Have any time-nuts got any data on the long term stability or drift
> > rates/ageing characteristics of thermistors? I am concerned with  ability
> > of holding temperature constant at the milliK level for years. I reckon
> > that if one can measure it one can control it. Conversely if one can't
> > measure it, because of the instability of the sensor,  one can't control it.
> > 
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