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Re: Capacitor charge, were is it?

On 10/28/96 22:25:36 you wrote:
>
>> Subject: Re: Capacitor charge, were is it?
><MASSIVE SNIP>
>
>Good post Bert,
>
>You've put into similar words what I just wrote in reply!  (I was away 
>for the weekend.)  The charge resides in the dielectric because that is 
>where the work was done.  In solid dielectrics it is referred to as 
>polarization (molecular gig goin' on here).  In space, (no molecules) the 
>purity of the charge retention by space itself is amazingly deceptive.  
>Another point you noted is that the solid dielectric/air junction is a 
>surface value or feature!  This is significant and bear back to the 
>original post I made regarding interfacial points of differing dielectric 
>constants.  To have a capacitor, at least one metal or conductive surface 
>must be present at all times, somewhere.  The capacitors we are used to 
>involve soild dielectrics and two separate plates.  Charge spearation can 
>even occur between two different dielectrics.  Charges and electrostatic 
>goings on are a dielectic related thing.  To make them do work we need 
>the metal stuff to collect them and transport them.
>
>I noted one post making a little jab at what would certainly be me 
>regarding to much theoretical concerns here.  Man this is where theory 
>shines and fails.  It seems its all theory and real hard to grasp 
>intuitively.  Frankly, I think a lot of thoughts on this area are just 
>that!  There is only one true physical reality but lots of thoughts and 
>intellectual wind gusts.  I'm not so sure science has the grip on this 
>subject to the degree they would like.  We got equations up the wazoo 
>which when solved yield solutions to real work problems but the little 
>minutia and quatum goes on at the gut level are still just a crap shoot 
>in our understanding.  No one really knows more than a broad overview. 
>(more than sufficient for real world apps)
>
>Richard Hull, TCBOR
>

Just to throw in my two cents worth, I agree with Richard.  The matter of 
dielectrics is an interesting one.  Having worked with some pretty novel 
stuff in my professional history, I have had ample opportunity to develop 
some interesting capacitor applications based on dielectric properties.  One 
of these devices was a capacitance hydrophone that worked using water as a 
dielectric.

Water as a dielectric has one particularly interesting property and that is 
that the relative dielectric constant is about 80!  This means that you can 
obtain a relatively high value of capacitance with smaller area.  Have you 
ever heard on anyone using a water based capacitor?  I suppose one would 
have to use degassed, deionized water, and I might expect that the breakdown 
voltage would be relatively high if the water had no contaminants.

Any comments?

Phil

Phil Gantt (pgantt-at-ix-dot-netcom-dot-com)
http://www-dot-netcom-dot-com/~pgantt/intro.html