Natural Science Forum / Physics / Electromagnetism / March 2008

Imagine I have an air-cored transformer.  This has some frequency response
up to (say) 100MHz where it tails off.
Then I insert a ferrite core.  This increases the mutual inductance so I
have a greater frequency response at low frequencies.  But at high

Invention is the marriage of mechanics and the sciences With
innovations in both fields.
I am an inventor of highly innovative technology. The technology is
basic at best.

The title of the post pretty much says it all.
The participants of this list seem to have fairly clear agreement that the
primary *cause* of magnetic fields is the motion of charges.
With a few hold-outs, most folks seem to (finally) understand that an E

I have to mathematically model a metal rod moving inside a coil. When
I move the rod through the field, the emf is induced between the ends
of the rod causing current to flow. This will recharge a large
capacitor able to supply the necessary current to a resistive load.

Popular Science, p. 208 (April 1945)
"Ehrenhaft Discovery Confirmed by New Experiments"
"By observing whirligigs of electrically charges particles in a
magnetic field, Brother Gabriel Kane of Manhattan College and Charles

I think now that it does.
Simple experiments, performed by Oleg D. Jefimenko and others
have shown electric field-lines around the wiring of some electric
circuits.

I have come to the conclusion that the Big Bang Theory is another
creation myth that sounds like a fairy story.
Thanks from Turtle

I have been toying around with some matlab code for FDTD simulations.
Running a simulation for a patch antenna, I get S parameters just slightly
larger than 0dB below a few hundred MHz. My assumption is that I have
either a DC offset in the simulation or the excitation pulse does ...