Modern Electronics (was Re: List charter mods & headcount... ; -))

From: der Mouse <mouse_at_Rodents.Montreal.QC.CA>
Date: Mon Jun 21 18:03:04 2004

>> I think you would have problems with cross-talk between the open
>> tubes, unless you limited your design to a single tube, or had large
>> spaces between the tubes.

>> The glass does more than just hold the vacuum, it is also an
>> insulator.

> If your tubes, envelopless, are already in an ambient vacuum -
> interplanetary space, the surface of the moon, etc - pray tell me
> what there is to 'insulate' against?

> What precisely, would be the mechanism of the 'cross-talk'?

As for plausible mechanisms that glass will stop but vacuum won't, I
offer the possibility that electrons from one cathode miss that valve's
plate and strike another one's.

I suspect the degree to which this happens depends on the geometry of
the electrodes and how one valve is mounted relative to another.

> [...] I can tell you that a quad of 6L6GCs, having had their glass
> envelopes carefully removed, operate as per spec when relocated to a
> bell jar

That is a very interesting experimental result. Thank you.

You don't describe enough details for me to more than take guesses at
the geometry of their mounting, and I don't know the geometry of their
electrodes. I would guess that they are basically cylindrical with
solid plates and you mounted them as parallel cylinders with coplanar
ends, in which case electrons that miss one plate are unlikely to go
very near another. I suspect that if you (a) mounted them such that
this is not true (say, two of them forming a T shape) and (b)
specifically looked for effects produced by current from one valve's
cathode to another's plate, your results would have been different.

/~\ The ASCII der Mouse
\ / Ribbon Campaign
 X Against HTML mouse_at_rodents.montreal.qc.ca
/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
Received on Mon Jun 21 2004 - 18:03:04 BST