[email protected] wrote on 06/10/2009 03:13:19 AM: > In message <[email protected]>, Bruce Griffiths writes: > > Bruce, > > >>> The thermal time constant (not the thermal impedance per se) is what > >>> matters [...] > > That is pretty much exactly the (mis-)definition of thermal impedance. > > Thermal timeconstant or thermal corner-frequency had been much > better names. > > >>> It is possible to construct an enclosure with a long thermal time > >>> constant together with relatively low thermal resistance so that the > >>> temperature of a GPSDO or similar device within the enclosure only > >>> increases by a relatively small amount. > >> > >> Nope. This is essentially a thermal low pass filter. > > Well, yes you can, but it is not very useful: > > A really huge block of metal will do that: It can transfer a lot > of heat (=low resistance), but will take a long time doing so (=high > impedance).
I read somewhere the suggestion to take the cast iron block from an old automobile engine and put it in a heavy insulated wooden cabinet: ~250 Kg of iron in an insulated box. Cracked blocks are useless in an engine, and so are available in junkyards quite cheap. Joe Gwinn _______________________________________________ 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.
