Hi Actually a primary temperature standard (triple point cell) is about the cheapest primary standard you can buy these days. A very good one (~ 0.1 mK) is still in the $1K range.
If you are ok with basic glass work (or know somebody who is) you can make a quite adequate one (~1 mK) for sub $100. If only you could build your own Cesium standard for $100 ... Bob On Nov 8, 2010, at 7:45 PM, Neville Michie wrote: > A hint for using peltiers, > the resistive component in them has a problem with IsquaredR heating > so that better performance is obtained by running them on filtered DC. > PWM control works best if it is filtered to DC. > > My choice for temperature control is a glass encapsulated thermistor, > there are some quite small ones that have very fast response and good ageing > performance. > > Diodes and transdiodes also make good sensors and can come in good packages > with rapid response. > > For us the best temperature standard is ice point and that is only good to 10 > mK. > Anything better means a trip to a standards laboratory. > > However, one is to be applauded for trying to link temperature to frequency, > > cheers, > Neville Michie > > > On 09/11/2010, at 2:04 AM, Poul-Henning Kamp wrote: > >> >> I'm contemplating building a small temperature control enclosure for >> testing various electronics. >> >> I have a handful of peltiers suitable for the purpose, and was >> pondering the right control mechanism. >> >> Most people would reach for a NTC, put it in a wien-brige etc etc. >> >> But since I happen to have access to much more stable frequencies >> than voltages, I thought of a different way: >> >> 1. Mount a X-tal-osc with really lousy tempco inside the enclosure. >> >> 2. Compare its output to a stable reference frequency. >> >> 3. Use the output of the phase comparator to drive the Peltier. >> >> It is basically a PLL where temperature is used as EFC... >> >> Has anybody tried that ? >> >> -- >> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 >> [email protected] | TCP/IP since RFC 956 >> FreeBSD committer | BSD since 4.3-tahoe >> Never attribute to malice what can adequately be explained by incompetence. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
