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)
<<attachment: 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.
