>>>** My position is that AC circuit-analysis is valid
>>>today, was valid >before I was born, and will be
>>>valid long after I am outta here.<<
>
>That would be a good assumption to re-think. "AC
>circuit-analysis" (by this, I assume you are referring
>to sinusoidal steady-state analysis using phasors,
>neglecting the real part, because I actually don't
>think anybody on this list has ever mentioned
>performing the calculations in their indigeonous
>LaPlacian space) is based on the notion that we can
>take an analysis technique developed for DC, apply
>some approximation equations to reactive impedances,
>and all will be well as we perform algebraic
>manipulation.
>
>Those who created equations such as Xl=2*pi*L*F and
>Xc=1/(2*pi*C*F) knew full well that they are not
>exact, they are mere approximations, because
>capacitance and inductance, as we know them, are
>defined only at DC. Those approximation equations
>fall apart when the physical dimensions of our
>components begin to approach a fraction of a
>wavelength. Because we have a lot of technicians
>attempting to perform engineering work, all manner of
>patchwork gets done, patching up the flawed models of
>components, claiming that we can "model" a "capacitor"
>by adding an inductor and a resistor in series with
>it. In many ways, we are forced to do such things,
>because the analysis tools we are given, depend on
>such models.
>
>The reality is that there is no such thing as a
>capacitor that behaves according to that equation over
>all frequencies, but you can certainly create a
>transmission line model of that capacitor that works
>over all frequencies.
>
>At frequencies other than DC, we are always working
>with fields, not volts, amps and ohms. We have been
>fortunate, thus far, to operate at frequencies where
>we can patch our so-called "AC circuit analysis" and
>make do with it, but that time will draw to an end
>before many of us have passed on. Thankfully,
>computer power is now reaching a point where it is
>possible to envision a time when our "circuit solvers"
>are actually performing 3D Maxwell field solutions.
>
>For about four years, my own professional work has
>been completely untenable with the so-called AC
>circuit analysis.
>
>Not that this is germaine to any discussions on AMPS,
>but it is critical, in any scientific/engineering
>discussion, to understand the limits of the models we
>use.
>
** agreed. However, Newtonian physics works fairly ok below 99% of the
speed of light.
>So-called AC circuit analysis began life as an
>approximation which was necessary in order to fit
>things into the limited ability we had to understand
>and solve real-world problems. And it will always be
>an approximation, nothing more. To claim it is valid,
>one MUST be able to elucidate its many limitations.
>
>
Valid points, Dave, however for analyzin' 100MHz or so L/R
parasitic-oscillation suppression, the albeit archaic, conventional stuff
is good enough.
** Have you met W8JI in person ?
cheerz
- R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
www.vcnet.com/measures.
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