Re: Addendum-DC Tesla

Tesla List wrote:
> >From jim.fosse-at-bdt-dot-comFri Aug  2 23:01:54 1996
> Date: Fri, 02 Aug 1996 15:38:46 GMT
> From: Jim Fosse <jim.fosse-at-bdt-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Addendum-DC Tesla
> >From: Richard Hull <hullr-at-whitlock-dot-com>
> >To: tesla-at-pupman-dot-com
> >Subject: Re: Addendum-DC Tesla
> >
> > This interesting method of rectification and elecron emission (field
> >emission) is seeing a modern revival in HV diodes and miniature X-ray
> >tubes.
> Richard and Malcolm,
>         An aside: Several years ago a field emission triode vacuum
> tube was announced in one of the electronics trade journals. They are
> made by 3 dimensional etching, in silicon, millions of micron sized
> field emissive cathodes. Various steps were then used to build up a
> cylinder, cap it, etch a grid over it, build up a cylinder, cap it and
> make the plate.  Field emissive cathodes are also being used for
> flat-pannel vacuum fluorescent (that is: cathode ray ) displays. It
> amazes me how technology can go in circles right back to a starting
> point.
> > All you need is a material of high work function and microscopic
> >surface area to emit electrons.  High voltage isn't even needed with
> >proper design!!
> >
> How about 2 materials of different work functions? Say, aluminum and
> air. copper and air or polyethylene? The first would explain the
> output rectification being proposed/observed here, the second the high
> static charge build up on the secondary coil former.
>         Regards,
>         jim


You are corect in all statements in your post.  Electrostatics and its 
implications are making a major comeback with a lot of older ideas being 
dusted off or being "rediscovered" like something really amazing!!

I have seen some special tubes built for a program funded by private 
research (sorry no names)  where razor blades (single edged) were used as 
the emitter and grid sections in sealed vacuum tubes ( triodes and 
diodes).  They worked great, but the funds dried up prior to definitive 
production units being tested in service.  With no fils, tubes could make 
a comeback only on etched boards!

Richard Hull, TCBOR