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 <jebponso...@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.griffi...@xtra.co.nz > <mailto:bruce.griffi...@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 <kb...@n1k.org > >> <mailto:kb...@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 <jebponso...@gmail.com > >>> <mailto:jebponso...@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. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
