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Re: Capacitor charge, were is it?

Tesla List wrote:
> 
> > Subject: Re: Capacitor charge, were is it?
> 
> >From gowin-at-epic-1.nwscc.sea06.navy.milThu Oct 31 22:20:42 1996
> Date: Thu, 31 Oct 1996 09:46:41 -0500
> From: Dan Gowin <gowin-at-epic-1.nwscc.sea06.navy.mil>
> To: tesla-at-pupman-dot-com
> Subject: Re: Capacitor charge, were is it?
> 
> Tesla List wrote:
> >
> > >From lod-at-pacbell-dot-netWed Oct 30 21:30:30 1996
> > Date: Sun, 29 Oct 1995 23:18:12 +0000
> > From: GE Leyh <lod-at-pacbell-dot-net>
> > To: tesla-at-pupman-dot-com
> > Subject: Re: Capacitor charge, were is it?
> >
> > Richard Hull wrote:
> >
> > <snip>
> >
> > > The idea that there are actually a quantity of electrons stuffed on a
> > > metal plate is pretty stupid and somewhat niave.
> >
> > How would you then explain the operation of a classic electrometer, where
> > two gold leaves suspended in a vacuum repel each other, when a charge is
> > deposited upon them?
> > I think that the main point of contention in this argument is simply the
> > definition of the word 'charge'.  For the sake of discussion, I would like
> > to suggest the classical definition, where charge is measured in coulombs
> > and the charge on a electron is 1.6 e-19 coulombs.
> > Energy (or work) is measured in Joules, which has units of volts X coulombs.
> >
> > > Have you ever brought
> > > the back of your arm up to a slab of metal WITH NO POWER SOURCE
> > > ATTACHED and felt the hairs stand on end? ( I THINK NOT!)  What about a
> > > piece of teflon or styrofoam?  (ALL THE TIME)
> > > Where is the REAL charge retained?  (the dielectric).
> >
> > Actually, a dielectric need not possess a net charge in order to store
> > electrical energy.  Energy (not charge) is stored in a dielectric by
> > distorting the orbits of electrons around atoms (like cocking a spring),
> > thereby producing an electric field. It is the electric field that moves
> > charge around on nearby conductors (or arms).  If the number of electrons
> > and protons in the dielectric are equal then it has no net charge, regardless
> > of how much stored electrical energy it might contain.
> >
> > -GL
> 
> All,
>         I brought up the point of the electrometer that Benjamin
> Franklin used as a simple example of a device that contains no
> dielectric. There are also simple instance were a charge can be
> placed on normally nonconductive substances (i.e.: a rubber mat).
> But this all roots itself back to a fundamental law of physics
> we should all remember. Electron flow (i.e.: the bucket effect),
> resides on the surface of an object. For example a wire containing
> multple conductors will have less resistance than a solid conductor
> will have. The reasons for this result are simple, more surface
> area. This is also the same for capacitor construction. More surface
> area to collect the charge and less distance between the plates
> tends to increase the potential.
> 
>         In the reverse, more dielectric does not mean more charge
> and more metal in the plates does not mean more charge. The key
> here is surface effect.
> 
> What does this mean? Well the charge is not in the dielectric! And
> the charge is not in the plates either! Its on the surfaces of these
> two different materials.
> 
> Enough!
> D. Gowin


D.

You have hit on what I have been saying all along about the dielectric/ 
metal interface being the point of charge separation... IN A CAPACITOR 
AND A CAPACITOR ONLY! IF A CHARGED CAPACITOR IS DISMANTLED, THE CHARGE IS 
ONLY FOUND IN THE DIELECTRIC AND ZERO CHARGE IS RETAINED BY THE PLATES.

Thus, you are right and wrong at the same time!

Only a dielctric can store charge!  In a capacitor the charge separation 
occurs at the metal/dielectric interfacial points. It is still held 
totally within the dielectric, however, until some closed metallic 
circuit conditon occurs and the energy enters the metal plates and goes 
off to do real work.  The dielectric or space within the dielectric gives 
this charge up to a willing conductor in a closed circuit which can 
neutralize the charge held on the opposite side of the dielectric and not 
on the opposite plate of the capacitor.  Sounds like semantics, but only 
one explaination works to explain experimental evidence.

Richard Hull, TCBOR