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Re: [Phys-L] circuit analysis : a simpler approach?

So it seems that kirchoffs laws work well for steady state circuits and
places in which using equivalent resistances work. They seem (to me)
functional and useful for an intro / general course that has chosen to
study only steady state circuits. Of course one could disagree with
choosing to study only steady state circuits, but that is a different
battle.

Is it better or worse to think of kirchoffs laws as conservation laws?
Loop rule as conservation of energy per charge.
Junction or node rule as conservation of charge.

The unasked question is, i suppose, if kirchoffs laws are functional and
useful in steady state circuits.
But i didnt ask that ;)

Have a good one.
Paul
(Where i hope my computer updates are done before our open house starts
tonight)
On Sep 2, 2015 9:43 AM, "Carl Mungan" <mungan@usna.edu> wrote:


On Sep 2, 2015, at 9:37 AM, Diego Saravia <dsa@unsa.edu.ar> wrote:

I was wrong, KL are not universal testing device.

Lets have a batery in a loop with 2 condensers. battery 1.5 V C1=1.5V
C2=0V

Its ok? ...... NO

if the previous conditions were B=1.5V C1=0V C2=1V, when you have a
switch
open, and close it


There are several conditions that satisfies KVL, but are not correct. all
VC1+VC2=1.5V


Well, doesn’t it depend on what you mean by “testing”?

C1=1.5 V and C2=0 V *is* a valid solution.

It’s just that it’s not the particular solution that is also consistent
with the initial conditions.

KL only checks that any given steady-state solution is physically allowed.
Time dependence is a separate issue.

-----
Carl E Mungan, Assoc Prof of Physics 410-293-6680 (O) -3729 (F)
Naval Academy Stop 9c, 572C Holloway Rd, Annapolis MD 21402-1363
mailto:mungan@usna.edu http://usna.edu/Users/physics/mungan/

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