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

From: Dwight K. Elvey <dwight.elvey_at_amd.com>
Date: Mon Jun 21 13:48:31 2004

>From: "der Mouse" <mouse_at_rodents.montreal.qc.ca>
>
>> There was an idea some time back that if we ever get to the moon that
>> we could be using "open-air" valves (tubes) in the vacuum there for
>> high powered devices
>
>Is the "open-air" vacuum on the Moon a hard enough vacuum for
>vacuum-tube technology? Does it depend on whether it's day or night
>(and therefore whether there is solar wind pouring in)? I know that
>_some_ vacuum-tube technology - notably CRTs - depends on electrons
>having a mean free path well over the tube size, and that needs a
>pretty hard vacuum.

Hi
 Even with all the solar wind, the surface of the moon has
a much harder vacuum than any of the tubes we have on Earth.
The moon does have a problem for such devices. That problem
is dust. It could be blocked with filters but that is another issue.

>
>> - with the benefit that goes with the better radiation resistance
>> that goes with valve technology.
>
>Is it valves that give you rad-hardening, or size? A transistor the
>size of a valve would, I suspect, be inherently pretty rad-hardened.
>(Certainly the largest transistors I've seen are far smaller than the
>smallest valve I've seen. Probably by about an order of magnitude,
>once you strip each one down to the operating portion.)

 There are still problems. A transistor can avalanche and not recover
without removing the power. A tube can recover with the power on,
as long as the metal don't ionize. So, it isn't just a size issue,
it is a materials issue.

>
>> It would be quite cool to watch a tv picture on an open CRT methinks.

 It would take less energy since much is lost by the thickness of the
Phosphor.
Dwight

>
>Possibly, though it would mean either suiting up or building the screen
>into a wall. :-(
>
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Received on Mon Jun 21 2004 - 13:48:31 BST