"Max Robinson" <[EMAIL PROTECTED]> wrote: > >When I was at the university I saw and worked on a thermostatic switch that >used a standard mercury thermometer. The little thing that clipped on to >the thermometer was the capacitor in an oscillator. The detector for >opening and closing the relay was a high Q tuned circuit. I saw them >regularly because I had to keep teaching lab instructors how to tune them up >before each use. In a controlled environment it might be possible to >optimize such a circuit for stable operation and tight control. My >intuition tells me that 1 degree is about as fine a control as you could get >unless you had a very narrow range thermometer with a small capillary. You >might be able to convert the existing thermostat to capacitive sensing. >That is apparently what Magnus is suggesting. > >Regards. > >Max. K 4 O D S.
Optical might work better. Maybe use the lens and laser from an old CDROM. It might be fun getting it to focus on the mercury column through a round glass tube. Or maybe the glass wouldn't even pass the infrared. I got a bad burn once picking up an empty wine glass that was sitting beside a fireplace. But I understand new systems use a blue laser, which might work even better. I wonder what kind of temperature control it would give, and what the long-term drift might be. Sounds like a fun project. Regards, Mike Monett _______________________________________________ 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.
