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Re: Unusual capacitor dielectrics



Tesla List wrote:

> Original Poster: Jacob Roberto <jroberto-at-ieway-dot-com>
>
> I've noticed that pure water has a dielectric constant of 80 (about 40 times
> higher than that of polyethylene). Would it be practical to build capacitors
> that use water as the dielectric? Such a capacitor could probably be
built by
> taking pieces of sheet metal, drilling holes in their corners, and then
> bolting
> them together, using nylon washers or other flat insulators to separate the
> plates.

    For this to work, the water needs to be incredibly pure, you need
$1000's of
purifying equipment running non-stop to keep the water pure enough and you
have to
coat all metal surfaces with a very non reactive metal, e.g. platinum. This is
because even the tiniest fraction of a gram of metal compound in the water
will
render it far too conductive for use as a capacitor. Water is used as a
coolant in
some high voltage systems, but as a di-electric, the difficulties almost
always
outweigh the advantages of it's high di-electric constant.

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