Hmmm. That sounds like something to be stored away for the day when my thermostat goes bad. Sounds like it would work.
Regards. Max. K 4 O D S. Email: [EMAIL PROTECTED] Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Music site: http://www.maxsmusicplace.com To subscribe to the fun with tubes group send an email to, [EMAIL PROTECTED] ----- Original Message ----- From: "Mike Monett" <[EMAIL PROTECTED]> To: <time-nuts@febo.com> Sent: Thursday, August 21, 2008 2:07 PM Subject: Re: [time-nuts] Restoring GR 1120-AB Frequency Standard > "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 -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.