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Old April 1st 06, 09:57 PM posted to rec.radio.amateur.antenna
Tom Donaly
 
Posts: n/a
Default Current through coils

Cecil Moore wrote:

K7ITM wrote:

I REGULARLY model transmission lines as "lumped elements" and do NOT
"presuppose that the speed of light" through them is infinite.



I'm interested in knowing how you model a shorted quarter wavelength
stub using the lumped element model.

I REGULARLY model op amps as "lumped elements" and do NOT presuppose
that the phase shift (and therefore propagation time) through them is
infinite.



I should hope not! You would never get a signal through them. :-)

I REGULARLY model inductors as "lumped elements", and do not presuppose
that they have no resistances and capacitances parasitic to their
inductANCE.



Then you are somehow applying a patch to the lumped element model.
The basic lumped element model assumes no resistance and no
capacitance. That's how the lumped inductance-only works in EZNEC.

I find that my models very reliably predict the behaviour I actually
observe in the circuits I build. I am served very well by the models I
use.



Do you use them on 75m bugcatcher coils and obtain an incorrect
phase shift as W8JI and W7EL have done?

By the way, what's EE203?



The sophmore EE class alluded to by Dr. Corum.


Cecil, there are two Corums and they're both Tesla coil
crackpots. Secondly, Tom is right, you have to have capacitance
to somewhere or your transmission line analogy becomes mired in
absurdities. Third, it isn't enough to think something up in
your head to make a convincing theory, you have to be able to
predict behavior with it. Finally, you have to understand your
subject before you even start thinking. I'm surprised you didn't
even take the time to make a real coil and at least try to
determine its characteristics before wasting everyone's
time by starting this thread.
73,
Tom Donaly, KA6RUH