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Re: VTTC from Eimac 8755 on eBay
Original poster: westland <westland@xxxxxx>
I didn't know you could do that with a transistor (any specific
type?) but ... yeh ... why not deconstruct a mass market device ...
you know it's going to be priced at the marginal cost of production
(which means that all the R&D and last minute sweating by the
engineering group to actually get a production version of the device
has been priced out at pretty close to zero) ... there's no way you
could compete with your own device.
But it may be a bit upsetting to the Varian engineer that designed
the anode of the 8755... nobody wants his work
Tesla list wrote:
Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>
At 04:52 PM 2/3/2007, Tesla list wrote:
Original poster: westland <westland@xxxxxx>
It's interesting how they use it as an electron gun ... they break
off the top part of the ceramic, and they pull off the anode ... I
guess leaving them with a cathode gun and a grid to modulate it.
As the fascinating tome on building your own lab gear ("Building
Laboratory Apparatus" by Moore, et al.) says:
"Don't build your own electron guns. They're a commodity item, and
a lot of time and money has been spent by the mfrs figuring out how
to make them."
To that, I will add some observations of how they design and build
things like TWTs.. designing and *building* a high performance
electron source is very much an art. Sure, any competent hardware
hacker who can run a vacuum pump can go out and heat a hot filament
up and spew some electrons through an anode to make a beam. Heck,
Thomson did that back in the 19th century. But to get a consistent
flux, with good life, etc. is definitely non trivial.
If I knew of a tube that had the right electron optics
configuration, I'd do exactly the same thing. (hey, is it any
different than sawing the can off a transistor to make a photo detector)
Jim Lux
--
____________________________________________________
J. Christopher Westland, PhD CPA
Professor, ISMT, University of Science & Technology, HK Clearwater
Bay,Kowloon, Hong Kong
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