[time-nuts] Restoring GR 1120-AB Frequency Standard

[Max Robinson]

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: max at maxsmusicplace.com

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,
funwithtubes-subscribe at yahoogroups.com

----- Original Message ----- 
From: "Mike Monett" <XDE-L2G3 at myamail.com>
To: <time-nuts at febo.com>
Sent: Thursday, August 21, 2008 2:07 PM
Subject: Re: [time-nuts] Restoring GR 1120-AB Frequency Standard


> "Max Robinson" <max at maxsmusicplace.com> 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 at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>