And if you are not in a well air conditioned room.... Gilles. Envoyé de mon iPad
> Le 12 juil. 2019 à 18:12, Javier Herrero <jherr...@hvsistemas.es> a écrit : > > Hello, > > A TEC is good if you want to maintain the resistors at 25ºC, that seems the > zero TC point for some precision low TCR resistors (for example, the Vishay > VFCP or VSMP series) > > Regards, > > Javier > >> On 12/7/19 10:06, Dr. David Kirkby wrote: >>> On Fri, 12 Jul 2019 at 08:07, Bernd Neubig <bneu...@t-online.de> wrote: >>> >>> AXTAL has a miniature oven for heating precision resistors or other >>> components to a constant temperature. It is housed in a small DIP8 package. >>> See attached AXR135 data sheet. >>> Optionally this device can be offered unsealed, ready for inserting the >>> component by yourself >>> >>> Regards >>> Bernd >> >> The resistors I am using are made by Caddock, are 1 M ohm & 10 M ohm, 0.01% >> tolerance and 5 ppm / deg C. They are much too large to fit in a DIP8 >> package. A quick check with a ruler indicates that the 10 M ohm is 38 x 12 >> mm and the 1 M ohm is 19 x 10 mm. >> >> A quick photograph shows this half finished project. Unfortunately, even >> before I have finished it, I am wishing I had done a better job. However, >> my original reason for doing this was to check the stability of a data >> acquisition unit before sending it to Keysight. I think this will be good >> enough for that, but I could certainly have done a job with some thought. >> >> The thermocouple is just meant to be a temperature sensor that dissipates >> no power. A thermistor or RTD buried in the polystyrene would have just got >> hot. The resistors should not get hot, as the power dissipated will be >> under 1 uW. >> >> I also intend putting in a 100 M ohm resistor, but the specification of >> that is much poorer (5%, 100 ppm/ deg C. ) >> >> I partially read the paper mentioned. I note that the authors used a thermo >> electric cooler (TEC) as they wanted get low temperatures. I assume that >> for crystals or resistors dissipating little heat, a TEC would be >> unnecessary, and just a resistor acting as a heater would be fine. But will >> read some of the references. Obviously for controlling a crystal >> oscillator, or my resistor, stability is most important, whereas for the >> authors of the paper, stability was not their major concern. >> >>> -- >> Dr. David Kirkby, >> >> _______________________________________________ >> 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. > > -- > --------------------------------------------------------------------------------- > Javier Herrero > Chief Technology Officer EMAIL: > jherr...@hvsistemas.com > HV Sistemas S.L. PHONE: +34 949 336 > 806 > Teide 4, Núcleo 1 Of. 0.1 FAX: +34 949 336 > 792 > 28703 San Sebastián de los Reyes - Madrid - Spain WEB: > http://www.hvsistemas.com > > _______________________________________________ > 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.
