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On Mon, 17 Apr 2000 14:36:39 -0400, I wrote:approximations:
. . .
Kirchhoff's laws are tantamount to making two simplifying
significanta) A capacitor is a two-terminal black box, and there are no
thecapacitances outside of capacitors;
At 10:18 PM 4/18/00 -0700, Bob Sciamanda wrote:
It is not necessary to place this burden on Kirchhof's loop law. It is
valid even for non ideal capacitors and inductors; eg, it even works for
an open circuit - a highly fringing capacitor situation.
When I spoke of K's laws, I spoke of laws plural (the voltage law *and*
current law) for a reason. As I see it, there are two ways to describe
Bob's open circuit:
1) We blithely ignore the current that flows into the "highly fringing
capacitor situation" (a current that violates K's current law), or . . .
2) We model the current that flows into this "stray capacitance" byvery
including in our analysis a "stray capacitor" that doesn't show up in the
fabrication parts list, and has a value that cannot be determined from the
usual sort of circuit diagram. (This makes K's laws formally correct, but
alas the real physics guarantees that any correct version will be very
hard to apply in the real world of fringing fields.) . . .