You can buy cheap ceramic room heaters which worh this way.
Peter On Jan 18, 2012, at 11:38 AM, Bob Smither <[email protected]> wrote: > Attila Kinali wrote: >> On Fri, 13 Jan 2012 12:50:19 -0500 >> "Bob Camp" <[email protected]> wrote: >> >>> The gizmo on top of the crystal is a rapid transition thermistor. The >>> Russians came up with them for use in OCXO's back in the 1970's. It's there >>> to heat the VCXO crystal, sort of an OCXO. >> >> Do you have any references to this? I couldn't find anything on the net. >> >> Attila Kinali > > From http://wb9ipa.qrpradio.com/60meter/osc_filter/osc_filter.htm : > > "PTC thermistors exhibit a unique behaviour, in that their resistance > increases > as the temperature increases. This temperature to resistance relationship is > very non-linear; in fact, the change becomes very rapid above a temperature > known as the Transition Temperature. This property can be exploited to make a > very simple, self-regulating heater." > > See also http://c-c-i.com/node/165 for an application note that has a pretty > good discussion of this. > > -- > Bob Smither, PhD Circuit Concepts, Inc. > ========================================================================= > Friendly relations with all nations, entangling alliances with none. > --Thomas Jefferson > ========================================================================= > [email protected] http://www.C-C-I.Com 281-331-2744(office) -4616(fax) > <smither.vcf> > _______________________________________________ > 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.
