[time-nuts] Ancient OCXO in scope calibrator.

[Scott McGrath]

The interlinked cup hooks are a fuse or fusible link.  there may be
others as EIA only standardized symbols in the late 60's and Mid 70's
  Just look in older HP documentation and see how many symbols they
used for zener diodes!.



On Wed, Sep 10, 2008 at 1:12 PM, David C. Partridge
<david.partridge at dsl.pipex.com> wrote:
> Now that's an interesting thought.
>
> How should one go about specifying such a part?
>
> Do you have any experience of doing this?  We'd be looking at (I guess) a
> turnover from almost short circuit to darn near open circuit over a range of
> a few degrees centred on 75 celsius.   Do such beasties exist?
>
> If it's relevant there are two heater windings, one for 230V, one for 115V
> though both do go through the thermostat.
>
> This rather surprised me as I would have expected two windings and only use
> one for 115V, and switch the second in series for 230V, but if I'm reading
> the circuit diagram right (not g'teed) this isn't what happens (it's on the
> last schematic page which is the power supply for those who've donwloaded
> the manual from BAMA).
>
> There's also something connected between the two windings which looks a bit
> like two cup-hooks - what this is I'm not sure.
> I don't recognise the symbol at all, it could just represent the bimetal
> strip part of the thermostat.
>
> I also don't quite understand the point of the capacitor at the top end of
> the 230V winding.
>
> Cheers
> Dave
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Neon John
> Sent: 10 September 2008 01:20
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Ancient OCXO in scope calibrator.
>
> I was just sitting here thinking about the oven problem.  If you replace the
> thermostat with the proper power PTC thermister, you could make the oven
> linearly regulate at a single temperature.
>
> John
> --
> John De Armond
> See my website for my current email address http://www.neon-john.com
> http://www.johndearmond.com <-- best little blog on the net!
> Tellico Plains, Occupied TN
> Multitasking: Reading in the bathroom!
>
>
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