Magic capacitors!
in [Design]
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From: Tim Williams on 21 Jul 2010 13:58 "Michael Förtsch" <michael.foertsch(a)chello.at> wrote in message news:57c17$4c46f981$5472c223$14009(a)news.chello.at... > The total electrical energy after the charge has been transfered is 50% > of the electrical energy that was stored in C1. The residual 50% had > been handed to the government as a charge transfer tax. Wrong -- the inductance and resistance of the circuit is unspecified, so 1., there is no correct answer, and 2. it's a nonphysical circuit, so not only is it unspecified, it's meaningless. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms
From: George Jefferson on 21 Jul 2010 13:59 "Tim Williams" <tmoranwms(a)charter.net> wrote in message news:azG1o.20990$lS1.2654(a)newsfe12.iad... > "Michael F�rtsch" <michael.foertsch(a)chello.at> wrote in message > news:57c17$4c46f981$5472c223$14009(a)news.chello.at... >> The total electrical energy after the charge has been transfered is 50% >> of the electrical energy that was stored in C1. The residual 50% had >> been handed to the government as a charge transfer tax. > > Wrong -- the inductance and resistance of the circuit is unspecified, so > 1., there is no correct answer, and 2. it's a nonphysical circuit, so not > only is it unspecified, it's meaningless. WRONG. That has nothing to do with it. We can "specify" that the inductance and resistance is 0. Just because this is physically not possible does not mean we cannot create such a hypothetical mathematical model.
From: Richard Henry on 21 Jul 2010 14:09 On Jul 21, 10:17 am, "George Jefferson" <phreon...(a)gmail.com> wrote: > "John Larkin" <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote in message > > news:dj7e465sga7fe3nq7hfl3f0uk601pvrem8(a)4ax.com... > > > > > On Wed, 21 Jul 2010 11:19:31 -0500, "George Jefferson" > > <phreon...(a)gmail.com> wrote: > > >>"John Larkin" <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote in > >>message > >>news:s43e46la1p1vt11527eg3ptl9ulm44dfrj(a)4ax.com... > >>> On Wed, 21 Jul 2010 07:54:03 -0500, "George Jefferson" > >>> <phreon...(a)gmail.com> wrote: > > >>>>Suppose you have two capacitors connected as > > >>>>--*-- > >>>>| | > >>>>C1 C2 > >>>>| | > >>>>----- > > >>>>where * is a switch. > > >>>>What is the total energy before and after the switch is closed(in > >>>>general). > > >>> Energy is conserved, so it's the same, if you account for all the > >>> manifestations of energy. > > >>You didn't answer the question. I assume this because you don't know. > > > State the question unambiguously and I will. > > > As I said, the puzzle is both ancient and trivial, so probably JT > > invented it. There are web sites and even academic papers devoted to > > it. Given all that, how could I not understand it? > > Um you don't get it. Your ignorance in basic electronics amazes me. Michael > got it(although he didn't explain where the energy went but I think gets > it). > > Assume the second cap is initially "uncharged" and has the same capacitance > as the first. > > Then the initial energy is > > Wi = 1/2*C*V^2 > Wf = 2*1/2*C*(V/2)^2 = 1/4*C*V^2 = 1/2*Wi > > Hence the final energy of the system 1/2 what we started with. > > I'd really like to hear your explanation but I know thats impossible(as > you'll steal someone elses). After all your the one that believes charge > isn't conserved... heres your change to *prove* it. Ignoramus.
From: keithw86 on 21 Jul 2010 14:19 On Jul 21, 12:59 pm, "George Jefferson" <phreon...(a)gmail.com> wrote: > "Tim Williams" <tmoran...(a)charter.net> wrote in message > > news:azG1o.20990$lS1.2654(a)newsfe12.iad... > > > "Michael Förtsch" <michael.foert...(a)chello.at> wrote in message > >news:57c17$4c46f981$5472c223$14009(a)news.chello.at... > >> The total electrical energy after the charge has been transfered is 50% > >> of the electrical energy that was stored in C1. The residual 50% had > >> been handed to the government as a charge transfer tax. > > > Wrong -- the inductance and resistance of the circuit is unspecified, so > > 1., there is no correct answer, and 2. it's a nonphysical circuit, so not > > only is it unspecified, it's meaningless. > > WRONG. That has nothing to do with it. We can "specify" that the inductance > and resistance is 0. Just because this is physically not possible does not > mean we cannot create such a hypothetical mathematical model. Ok, give us a mathematical model of "divide by zero".
From: The Phantom on 21 Jul 2010 14:35
On Wed, 21 Jul 2010 07:54:03 -0500, "George Jefferson" <phreon111(a)gmail.com> wrote: >Suppose you have two capacitors connected as > >--*-- >| | >C1 C2 >| | >----- > >where * is a switch. > >What is the total energy before and after the switch is closed(in general). > >If you want to make it easier assume C2 is initially discharged. > >Is the energy before and after the same? If not explain why and why it is >not a violation of the conservation of energy law. This is an old puzzle that has been dealt with before. The "lost" energy can be carried away from the circuit in various ways. Even if the conductors have no resistance, electromagnetic radiation will carry away energy. See these papers: http://www.hep.princeton.edu/~mcdonald/examples/EM/boykin_ajp_70_415_02.pdf http://www.hep.princeton.edu/~mcdonald/examples/EM/mayer_ieeete_36_307_93.pdf http://iopscience.iop.org/0143-0807/30/1/007/pdf/ejp9_1_007.pdf http://arxiv.org/PS_cache/arxiv/pdf/0910/0910.5279v1.pdf |