Relative Permittivity of Water

[TinselKoala]

Well, Torana seems to think that real, not ultrapure, water, or any substance with some conductivity, can't be used as a capacitor dielectric. Of course "that all depends". It all depends on the voltage and current available, as well as the characteristics of the container. I've done quite a bit of laboratory work discharging high-voltage arcs into water-filled chambers, and it's easy to see the ionization and electrolytic conduction phase of the discharge process on the scope traces.
But now I'm curious too. I'd like to see some real data, comparing, say, the polar liquid under question (Water) with a similar non-polar one (Carbon Tetrachloride, say) in a capacitor cell. I blew out my personal capacitance meter the other day, but maybe I can borrow one from somewhere.

[Torana]

Simple fact is a cap function is to block DC.     DC can not get thru the DIELECTRIC / INSULATOR.
How often have you read of an invention that uses tap or sea water in a cap?
Simple test using DC across water will reveal if its conductive.
If its conductive , can it be used as a dielectric??
The answer is obvious....
Thru simple elimination the 'invention' did not use tap or sea water as a component of a capacitor.

No where in the thread have I mentioned my own testing , Its open for anyone to test for themselves ,for their own benefit and confirmation.

Permittivity scale is for pure water and pure water ONLY, . ..80 .
Anyone considering construction of a "capacitor" needs to be aware that all other types of water are NOT included on the scale.
The formula , C = er x e0 x A / d ,applies to a non conductor NOT a conductive liquid. It cant.
As soon as there is DC conduction theres an electrochemical process , now your talking free electrons and ions.
Permittivity goes in the chapter on electrostatics while electrochemistry is in the inorganic chemistry chapter , same book , different chapters.  EIT reference manual .
HV water bridge is a good example of water conduction and experiment,try that one too.
Try testing over the counter capacitors , known functional capacitors.

[fritznien]

OK you almost have it. "normal" water is complex stuff, it might help to think of it as a composite material.
pure water makes a great dielectric,dirty water makes a leaky dielectric.
think of it as a cap and nonlinear resister in parallel.
the only water caps i know of are used in large high voltage supplies for atom smashers.
ultra pure water with constant de-ionization, cheap to build and no toxic chemicals when they fail.
as for the invention of course it didn't work,what do you expect its been 20 years with no progress, no results.
mother nature is a blabbermouth all you have to do is ask the right question.
fritznien

[Torana]

1-the 'invention ' hasnt worked for 20yrs , does that mean weve shot down stan meyer?
2-does that eliminate tap water and sea water as a non conductor/insulator/dielectric ?
1 and 2 are the same thing , so now weve knocked out 2 types of water so far.
Dirty water makes a great conductor and produces Hydrogen when DC is applied.
Try testing distilled water , we might aswell knock that out too.
Two SS plates 1/16 inch apart and use 12v DC
1-use a continuity tester between plates
2-use an LED test light in series with 12v DC .

The model of a cap is equivalent series R , equivalent series L ,and Capacitance in parallel with insulation R .  ( ESR, ESL , C and iR )
DC pretty much puches a hole thru insulation R in this case,  current measurement gives
R = V / I ,Ohms law

HV pure water caps fail? I would assume the water dielectric is self repairing, what does it break down into?
Now we're getting to breakdown voltage , current is the result of failure.
According to the rules, electric current flows thru water by riding on the ions IN the water...?
Are they using circuit breakers ? why not go in series for higher V rating.
Absolute pure water has to be enclosed in a sterile environment or it would be contaminated.
If the dielectric is broken down ,does the enclosed cap have compensation for expansion of H2O,
like a Bucholtz valve? If it self repairs would that then create a vacuum ?

None of these ?? are directed at you or any individual ,it just raises even more questions.

[Torana]

HV Van De Graaff generator =  electrostatic machine = DC output.
In this case the function of the cap is to BLOCK DC and store charge ,Q=CV,   Uc = .5 C V^2
Only pure water can be used in the caps, all other types of water are conductive and have no dielectric value at all.
Permittivity rating of 80 applies to pure water and pure water ONLY.
Thru simple testing of conductance shows tap water fails as a dielectric of any kind.
Test an electrolytic cap with continuity for 10 secs, a fully charged cap is an open circuit.
DATA;
Stans original SS "water capacitor" dimensions ;
5" x 1/2" pipe  plus   4" x 3/4" pipe with 1/16" wall thickness.
1; 5"=127mm,    1/2" =12.7mm dia
  perimeter = 2 x pi x radius = pi x 12.7 = 39.898227mm
  127 x 39.898227 = 5067.0748 AREA.
2; 4"=101.6mm,    3/4"=19.05mm  minus  3.175mm =15.875mm dia
  perimeter = 2 x pi x radius = pi x 15.875 = 49.872783mm
  101.6 x 49.872783 = 5067.0748 AREA.
3; gap between plates =1/16" = 1.875mm { d }  , between 2 equal size plates .

4; C = er x e0 x A / d  = theoretically  2.27 nf   (dreaming)

Its a personal choice to call it a capacitor, it all depends what the dielectric is.
DIELECTRIC;
Oxford dictionary = Insulating (medium or substance ) Non conductive, non conductor .
Collins dictionary = a material, as rubber , glass etc that does not conduct electricity ,non conducting.
Microsoft dictionary =...........?...

Dont use carbon tetrachloride