Re: Charge stored in Dielectric? Not really - MISCONCEPTION

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: robert & june heidlebaugh <rheidlebaugh-at-desertgate-dot-com> 

Just an added thought. In Oil you have added a second high dialectric with
active browniun movement to desperse and discharge the voltage charge. I
question the validity of your conclusion. In air with solid components no
large movement is taking place, only a local movement within the dialectric
surface this preventing the stored charge from being neutralized. An example
is the formation of a lectric where the dialectric is charged as a liquid
(wax) and then cooled to a solid before removing the charge voltage. The
charge is stored as a perminant electrostatic charge like an " electrostatic
magnet" in effect.
      Robert   H
-- 


 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > Date: Fri, 23 Jan 2004 20:12:56 -0700
 > To: tesla-at-pupman-dot-com
 > Subject: Charge stored in Dielectric?  Not really - MISCONCEPTION
 > Resent-From: tesla-at-pupman-dot-com
 > Resent-Date: Fri, 23 Jan 2004 20:18:47 -0700
 >
 > Original poster: dhmccauley-at-spacecatlighting-dot-com
 >
 >> Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
 >>
 >>
 >> A classic capacitor physics experiment.  Charge a Leyden jar.  Remove the
 >> plates completely and short them both together and to ground.  Reassemble
 >> the jar and it delivers it's normal spark.  Charge is stored in the
 >> dielectric.  The effect of the plates are completely eliminated in this
 >> experiment.
 >>
 >> Dr. Resonance
 >
 > Actually, I've been doing a lot of research into this since I last saw this
 > effect demonstrated at the Rochester Teslathon and have found this to be a
 > misconception.
 > I've also tried of few of my own experiments to verify this and to see what
 > was really going on.
 >
 > In the demonstration I saw, a capacitor comprised of a thin dielectric
 > separated by two flat aluminum plates was charged via a small flyback supply
 > to about 10-20kV.  The charging
 > supply was removed and then the capacitor carefully disassembled.  The
 > dielectric was removed and passed around the room for all to touch, etc...
 > and then the capacitor was
 > re-assembled.  Upon re-assembling the capacitor, you could once again draw a
 > big arc of it proving that the charge of the capacitor was still there and
 > it is concluded that
 > the dielectric stores the charge all along.  To further prove this, the
 > dielectric could be rolled up, mailed across the country, and assembled in a
 > separate set of plates and once together,
 > again an arc could be reproduced again proving that the charge is indeed
 > charged in the dielectric.
 >
 > However, this is not correct.
 >
 > What is actually happening is quite complex.  When the two plates of the
 > capacitor are moved apart, the total capacitance of the plate capacitor
 > drops and as a result, the potential
 > difference between the plates increases to enormous levels.  Because of the
 > physical arrangement of the two plates, this potential cannot increase
 > infinitely and instead it forms
 > corona along the outer metal edges of the plates and leaks the excess charge
 > into the surrounding air.  This corona (which can be heard during this
 > experiment) then allows
 > opposite electrical charges to be "sprayed" or "painted" onto both sides of
 > the internal dielectric material.  So when you dissassemble this capacitor,
 > this corona effect transfers a
 > large percentage of the separated charges from the aluminum plates onto the
 > dielectric surfaces.  The energy is still there, but its stored as a field
 > in the dielectric material.
 >
 > To further disprove this misconception, i did the two experiments which were
 > recommended to me by an old timer friend of mine.
 > With a similar set-up, I did the following experiments.
 >
 > 1.  I repeated the standard experiment.  I had two plates, measuring about
 > 6" x 6" and a thin dielectric.  I charged this plate capacitor up to about
 > 15kVDC using a small
 > EMCO DC-DC High Voltage Power supply.  I completely dissassembled the
 > capacitor, removed the dielectric, re-assembled the capacitor, and managed
 > to pull a
 > nice discharge from this capacitor.
 >
 > 2.  Now, to prove that the charge isn't stored in the dielectric and is
 > actually created by the corona effect on the separation of the metal plates,
 > I did the repeated the above
 > experiment in a basin of mineral oil.  When performed under oil, the corona
 > would be minimal and no "spraying" effect would be present between the
 > plates and the dielectric.
 > I repeated the experiment, charged the capacitor plates to 15kVDC,
 > dissassembled them, removed the dielectric, and then re-assembled them.  I
 > tried discharging this
 > capacitor now, and there was absolutely nothing.  I repeated this a few
 > times and still nothing.
 >
 > 3.  On the second version of the above experiment, I charged the plates in
 > air and dis-assembled them in air.  I then put the capacitor together under
 > oil, and voila, as I guessed,
 > I could pull a nice discharge from the capacitor.  On the reverse, I charged
 > the capacitor under oil, dissassembled it under oil, and then reassembled
 > the capacitor in air.  Again,
 > as I guessed, there was no discharge.
 >
 > 4.  On a final experiment, if the energy was indeed stored in the dielectric
 > as the Common Misconception goes, then it should hold true no matter what
 > the capacitor voltage
 > was.  So I repeated the experiments at a variety of low voltage (100VDC,
 > 200VDC . . . to about 500VDC)  I charged the capacitors up.  Checked the
 > voltage with a multimeter
 > to verify charge, and then dissassembled the capacitors. (Again, this was
 > done in air)  The capacitors were put together and the multimeter was used
 > again to check for any voltage.
 > Again, there was no voltage present in that newly assembled capacitor.
 > Thinking maybe the internal impedance of the multimeter was discharging the
 > capacitor before it could
 > take a reading, i switched to an electrostatic meter.  Again, the experiment
 > was repeated, and nothing.
 >
 > So in light of all this, you can clearly see that the charge really isn't
 > stored in the dielectric.  It just so happens that when performing the
 > dissectable capacitor experiment at
 > high voltages that other effects are occuring causing the dielectric to be
 > charged up by fringing corona fields created by the increased voltage
 > potential as the capacitor plates
 > are being separated.
 >
 > If anyone still doubts this, I challenge you to perform the experiment under
 > oil.  If the charge is *indeed* stored in the dielectric, you will be able
 > to reproduce this
 > dissectable capacitor experiment under oil.
 >
 >
 > Dan
 >
 >