[SI-LIST] Re: heat v. radiation Re: FEM/BEM/MoM

Lin, I respecfully disagree with your statement.

The lost energy can be partitioned arbitrarily=20
between heat and electromagnetic radiation,
depending on the circuit's geometry, R, and L values.
It's trivial to do the experiment and get mostly heat.
But I'm guessing that with some design effort,=20
one could get mostly radiation.

The transient behavior after switch closure is=20
generally oscillatory, damped according to losses.

Rich

> -----Original Message-----
> From: Lin Li [mailto:lilin@xxxxxxxxxxxxx]
> Sent: Thursday, August 28, 2003 12:31 PM
> To: gary_pratt@xxxxxxxxxxx
> Cc: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: FEM/BEM/MoM
>=20
>=20
> Heat transformation is not likely to happen unless the switch=20
> cable has very
> large resistance.
>=20
> We know at the moment of the electrons transfer, there will=20
> be a transient
> which will induce radiation. That is where the energy goes.
>=20
> I cannot deny heat effect but it is minor.
>=20
> Best,
>=20
> Lin
> **********************
> Lin Li
> Ph.D. candidate
> 3123 Glenn Martin Hall
> Mechanical Engineering
> University of Maryland
> College Park, MD 20742
> Ph: 301-405-5588
> ***********************
>=20
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx
> [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Pratt, Gary
> Sent: Thursday, August 28, 2003 1:08 PM
> To: arafi001@xxxxxxx; si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: FEM/BEM/MoM
>=20
>=20
> The quarter-Joule turns into heat when the switch is vaporized into a
> cloud of smoke.
> Whats the paradox?
>=20
> Gary L. Pratt, P.E.
> Product Manager
> High-Speed Design Kits
> Mentor Graphics
> (503) 685-1177
> gary_pratt@xxxxxxxxxx
>=20
>=20
>=20
>=20
> -----Original Message-----
> From: Abdulrahman Rafiq [ mailto:arafi001@xxxxxxx
> <mailto:arafi001@xxxxxxx> ]
> Sent: Thursday, August 28, 2003 12:36 PM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] FEM/BEM/MoM
>=20
>=20
> Geoff,
>=20
> Could you ellaborate on this a little more, as I am afraid i
> can't quite see what happened to the 1/4 Joule of energy.
> Perhaps if you could do a quick back of the envelope
> calculation as an example.
>=20
> -----------------
>=20
> Just a little diversion to show the error in a schematic:
> An old example often quoted is the problem of connecting two
> one farad
> capacitors together by a switch; one is at 1V potential, the
> other zero.
> The initial energy is 1/2 CV**2 =3D3D 0.5 joule.  After closing
> the switch th=3D
> ere
> is charge distribution, and energy =3D3D 1/8 +1/8 =3D3D 0.25
> joule.  Where did =3D
> the
> missing 0.25 joule go?  If you did an electrical degree,
> you'd see the
> paradox.  If you studied high frequencies, you'd know the
> answer.  (I did a
> Physics degree, then built RF circuits, so for me a capacitor
> is not a
> capacitor.)
>=20
> The answer is
> 1) it's not physically possible to put two capacitors
> together at one point
> 2) therefore they are separated by a distance
> 3) therefore on closing the switch, the discharge current
> travels a distance
> 4) the conductors have finite conductivity
> 5) therefore there is a varying electromagnetic field and
> energy is
> dissipated and radiated
> 6) please don't talk about too much about inductance because
> it's only an
> approximation.
> -------------------
> ---------------------------------------
> Abdulrahman Rafiq
> Department of Physics
> University of California
> Riverside, Ca. 92521
> Email: arafi001@xxxxxxx
> URL: www.geocities.com/arafiq786
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