Figure 5 in http://www.wenzel.com/wp-content/uploads/Sub-pico-Multiplier.pdf ?? Bruce > On 13 July 2019 at 05:23 Bob kb8tq <[email protected]> wrote: > > > Hi > > If you do go the TEC route, plan on a fairly big power source :). There is a > Wenzel doc on doing a TEC based enclosure using a couple of die cast > boxes. The pictures don’t show what they used to drive the beast so part of > it would still be up to you. My search skills and their web site are not quite > compatible so no link …. sorry !!! > > Bob > > > On Jul 12, 2019, at 12:12 PM, Javier Herrero <[email protected]> wrote: > > > > 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 <[email protected]> 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 -- [email protected] > >> 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: > > [email protected] > > 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 -- [email protected] > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.
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