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Keith Dysart wrote:
So you are saying that ideal voltage sources work differently in distributed networks than they do in lumped circuits. "Work differently" is a loaded expression. Since both lumped circuit and distributed network models exist, it is safe to say that the lumped circuit model and the distributed network model indeed "work differently". If they didn't "work differently", there would be no need for both of them to exist. Your previous error is obvious. You were using the lumped circuit model on the left side of Rs and using the distributed network model on the right side of Rs. If it is necessary to use the distributed network model for part of the network, then it is absolutely necessary to be consistent for all of the network. When you switched to the lumped circuit model on the right side of Rs, the energies balanced. When you switch to the distributed network model on the left of Rs, the energies will also balance. The lumped circuit model is a subset of the distributed network model. See: http://www.ttr.com/corum/ and http://www.ttr.com/TELSIKS2001-MASTER-1.pdf Here's some quotes: "Lumped circuit theory fails because it's a *theory* whose presuppositions are inadequate. Every EE in the world was warned of this in their first sophomore circuits course. ... Lumped circuit theory isn't absolute truth, it's only an analytical *theory*. .... Distributed theory encompasses lumped circuits and always applies." Where does the energy being absorbed by these ideal voltage sources go? 0+j0 ohms cannot absorb energy. As Eugene Hecht said: "If the quantity to be measured is the net energy per unit area received, it depends on 'T' and is therefore of limited utility. If however, the 'T' is now divided out, a highly practical quantity results, one that corresponds to the average energy per unit area per unit time, namely 'I'." 'I' is the irradiance (*AVERAGE* power density). You seem to have discovered that "limited utility". You have an instantaneous power calculated over an infinitesimally small amount of time being dissipated or stored in an impedance of 0+j0. Compared to that assertion, the Virgin Birth seems pretty tame. :-) -- 73, Cecil http://www.w5dxp.com |
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