22 Jan
2004
22 Jan
'04
7:25 p.m.
I do think one possible area of unexplored power-microwave tube
development might be a space-borne sun-heated filament magnetron or
something. Big collector on one side, fins on the other.
I'm not a tube nut, I just researched them for various projects. I don't
believe in illuminati conspiracies and 100 mpg carburetors either!
tomj
On Wed, 2004-01-21 at 01:31, Stan Barr wrote:
Hi,
William Donzelli <aw288(a)osfn.org> said:
See http://www.triodeel.com/area51.htm - if it still works.
...this
sounds as though it's the converse; this sounds as though tube
transit times are inconveniently _high_.
So I don't get it.
In theory, computing tubes would not use much power at all, so one could
space the cathode-grid-plate structure very close, and get the super
speeds due to the very short distances involved. Imagine tubes as small
today's transistors - the speeds would be fantastic, as the electrons
would speed right thru the micron of vacuum much faster that a micron of
silicon.
However, the real world hits the tubes far before element spacing gets
this tiny. The breakdown voltage between the cathode and plate probably
hits first - too close, and the electrons will simply jump over on their
own, like a spark. Likewise, with very short distances, capacitance will
become a big issue. The best conventional tubes top out somewhere around 4
GHz, and these were only good for small amounts of power. They were a
bastard to build, as well.
So, in a perfect world, with no capacitance or power problems, tubes
would be great.