Addendum
to Ivor Catt, Electronics
World, Addendum
written and uploaded on 24feb04 
Charge
spreading out across the plate of a capacitor 
Maxwell and later Heaviside did not realise
that a capacitor is a transmission line, along with all lecturers and text
book writers worldwide up to the present day. Looking at the conventional way
a capacitor is drawn, it appears that the problem the electric charge has,
entering the capacitor at only one point and then having to spread out over
the capacitor plate, is a trivial one. The distance the charge has to travel looks
small. Also, the way it is then
distributed seems complicated, but fast. This will lead to some readers of my
letter in Electronics World in April
2004 dismissing me as pedantic. Heaviside’s failure to notice that a
capacitor is a transmission line was not the only reason why he failed to
notice the flaw in what is said to be Maxwell’s greatest achievement, the “invention”
of “The Extra Current”, now called “Displacement Current”. Heaviside
described Maxwell a “The heavensent Maxwell, a man whose fame, great as it
is now, has, comparatively speaking, yet to come.” – O. Heaviside, Electrical
Papers, vol. 1, p438. Failing to notice that a capacitor is a
transmission line would have led Heaviside to fail to realise that the
electric charge spreads out across the capacitor plate very slowly. Whereas
the speed of light, or of a TEM step in a transmission line with vacuum
dielectric, is one foot per nanosecond, this speed depends on the dielectric
constant of the dielectric. If a capacitor’s dielectric has a dielectric
constant of 10,000, the speed of travel for the TEM wave and therefore the
speed with which charge spreads out across the plate of a capacitor will be
reduced by the square root of 10,000, down to one foot in 10 nanoseconds.
10nsec relates to a frequency of 100MHz. Thus, if a capacitor’s width is one
tenth of an inch but it has a dielectric constant of 10,000, a signal will
not traverse it in 100 picoseconds. The delay would increase to 10 nsec. When
you look at a tiny capacitor, you should try to regard it as very large with
difficulty in handling inputs of 100MHz. I have posted web pages ridiculing the
false idea of a capacitor’s “self resonant frequency”. Our December 1978 article asserted
that series inductance does not exist in a capacitor. No physical mechanism
has ever been proposed for the mechanism of unwanted series inductance, which
I attribute to the capacitor’s legs, not to its insides. At this point I need
to point out that the time delay in traversing the insides of a capacitor has
nothing to do with the phoney idea of self resonant frequency. That is, the
round trip across a capacitor and back does not relate to all the nonsense
published about “self resonant frequency”. If you investigate someone’s
experiment when he thought he was finding the “self resonant frequency” of
his capacitor, you will find that his result will depend on the length of the
legs he left on his capacitor, and will have had nothing do with the
capacitor’s insides, including the delay across the inside of a capacitor. Ivor Catt 24feb04 . 

Theory of Flight. http://www.ivorcatt.com/2606.htm
Displacement Current http://www.electromagnetism.demon.co.uk/z001.htm
http://www.ivorcatt.com/2635.htm
Catt Question http://www.ivorcatt.com/28anom.htm http://www.electromagnetism.demon.co.uk/catanoi.htm
Maxwell's Equations
http://www.ivorcatt.org/ic3804.htm http://www.ivorcatt.com/2804.htm
Moving Backwards. http://www.ivorcatt.com/2607.htm
TEM Wave. http://www.electromagnetism.demon.co.uk/17136.htm
http://www.electromagnetism.demon.co.uk/20136.htm
The Heaviside Signal http://www.ivorcatt.com/2604.htm http://www.ivorcatt.com/1_1.htm figures 4, 5. 