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Re: Capacitor charge, were is it?


A few pulsed power machines that I have
read about have used water as a capacitor
for pulse charging a sharpening gap.  It has to be
continuously deionized when in use.
Barry

 ----------
|From: "tesla-at-poodle.pupman-dot-com"-at-PMDF-at-PAXMB1
|To: Benson Barry; "Tesla-list-subscribers-at-poodle.pupman-dot-com"-at-PMDF-at-PAXMB1
|Subject: Re: Capacitor charge, were is it?
|Date: Friday, November 01, 1996 3:40AM
|
|<<File Attachment: 00000000.TXT>>
|>> Subject: Re: Capacitor charge, were is it?
|
|From pgantt-at-ix-dot-netcom-dot-comThu Oct 31 21:48:51 1996
|Date: Thu, 31 Oct 1996 02:11:50 -0800
|From: pgantt-at-ix-dot-netcom-dot-com
|To: tesla-at-poodle.pupman-dot-com
|Subject: 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
|