From: jim.fosse-at-bdt-dot-com (jim fosse)
Date: Wed, 21 Feb 96 23:48 PST
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>I have been messing around with liquid-dielectric plate capacitors...
>Anyone else ever used or dealt with a plate capacitor configuration using
>a liquid as a dielectric. I have been messing with using deionized NH4,
>deionized (distilled) H20, and glycerine. Anybody have any better ideas
>for the liquid dielectric?
If you want a much higher specific energy, use an NH4/LOX system - BOOM!
Oops, wrong list, this isn't rec.pyro
>A liquid-dielectric capacitor would be quite configurable. The temperature of
>the liquid dielectric effects the dielectric constant, plates are easily added
>, corona and flashover should not be to much a problem seeing as the entire
>assembly (conductor plate wise) is totally immersed in the dielectric (no need
>to mess with transformer/mineral oil on top). Dielectric breakdown due to
>inconsistancies in molecular structure (such as with polyethylene) is not as
>big as concern as with film capacitors. Just some thoughts...
>Also has anyone ever tried using a better conducting electrolyte in salt water
>capacitors, does it improve performance any? Here are some equivalent
>conductances of some electrolytes:
NaCl + H20 <-> HCl + NaOH
will disolve an aluminum plate -> Al0H + H2
not much effect on an aluminum plate.
>....above in 0.005 gram equivalents per 1000 cubic centimeters
>Hydrochloric acid appears a good choice, that is if you could keep it from
>destroying the electrode and wall of the vessel..:)
>Note that sodium chloride (table salt) is pretty low, I am sure their is a
>better choice for the liquid-conductor plates in "salt-water" capacitors.
>Question is does the conductivity of the liquid-plate electrolyte really
>make that big of difference in overall capacitor performance, or maybe I
>am just pissing in the wind...
Electrolytic caps use an electrolyte of ethylene glychol (sp) read
that as automotive antifreeze.
An electric current is then applied to produce a layer of aluminum
oxide on the anode plate. The oxide is the dialectric. Try it, either as an
electrolytic cap for dc or as a conductor for an AC cap using a seperate
dialectric. You'll still get a corona because it's a conductor.