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Water dielectric - the theory...
From: Daryl P. Dacko[SMTP:mycrump-at-cris-dot-com]
Sent: Monday, November 10, 1997 5:20 PM
To: Tesla List
Subject: Water dielectric - the theory...
At 06:12 AM 11/8/97 -0600, you wrote:
>
>From: Alfred C. Erpel[SMTP:aerpel-at-op-dot-net]
>Sent: Friday, November 07, 1997 6:07 PM
>To: tesla-at-pupman-dot-com
>Subject: Water As Dielectric
>
>
> Is distilled water considered to be a viable dielectric material for a
>plate capacitor? High voltage vs. low voltage? DC vs. RF? Since it's k=80+
>it would seem to be a good choice. As a toolmaker, I would have no problem
>making a sealed, watertight plexiglas cube, void of air, with evenly spaced
>copper plates inside, and I would like to do this if someone doesn't tell me
>it is a dumb idea.
> What is water's dielectic strength? I did a search on the internet for
>this value and the only thing I kept finding was it's dielectric constant.
I just did a bunch of reading on dielectric theory and how the dielectric
constant is related to dielectric dissipation vs. type of compound.
Whew !
Heavy stuff, but if I've gotten it all correctly, we can put to rest useing
any type of high dielectric constant materals, unless we are willing to
put up with high dissipation.
I finally found dissipation factors for water: about 4000 vs. .0002 or so
for polyethylene. Yipes !
The problems seems to be that only polar compounds have high constants,
and all polar compounds will have high loss, due to the same bending
motions in the compound that store all that energy.
Ceramics have high loss due to a hysteresis effect, that is an electrostatic
analog of the magnetic hystersis we see in our transformer cores.
I also found that most of the dissipation in polyethylene is due to
impuritys generated during processing - recycled PE is likely to have
a dissipation factor over 100 times that of virgin PE...
More later,
Daryl