There are many equations to describe what happens whenever
it does happen, but why does the current flow in the first place?
I used to think that it was electrostatic pressure caused by all
the electrons being bunched up against each other and so
pushing them apart, but someone said to me recently, that
the electrons are merely being dragged along by the travelling
electric wave.
So, why does the current start flowing in the first place
(when there is no wave to drag them along)?
And why does it keep flowing?
.... < Palpable bollocks deleted > ...
You are quite wrong in your assumed assessment of me.
I completed an electronics degree over 20 years ago, and looking at
the shelf of textbooks I mused that if I didn't get around to reading them
again soon, I never would.
So, out of interest, I started reading them all again, and came to the
conclusion
that there was a great deal left unsaid and unexplained, even at the degree
level.
I also accept that despite my level of education, that I do not know
everything,
and in pursuit of the truth, am prepared to admit my limitations in order
to achieve intellectual satisfaction.
I perceive now, that at whatever level one studies electricity, from the age
of
11 years upwards, that one is presented with a series of paradigms, none
of which are complete, and all of which are misleading to some extent.
Even at the level of Maxwell's Equations, electric charge is presented as
point
function akin to mass, whereas the physicist might claim that the electron
is
not a point, but a wave function.
So, as a part of my extended revision, I awakened the paradigm of electrons
being bunched together against their mutual repulsive forces (the "packing
density" sneered at in another post by a further example of rampant
childhood)
and the electric current (and I am definitely discussing electrons and not
positive
ions) being caused by that pressure from the electric field.
However, in discussion with a fellow radio ham (for such am I also) he
suggested
that the current flow in a waveguide is not caused by the mutually repulsive
electric field between electrons, but that the electrons are carried along
under the
influence of a travelling e-m field and that the original emf that set the
wave in motion
is no longer relevant.
Hence the question that I posed.
Perhaps I was in error in posing a question about elementary matters in
language
that was itself more redolent of the elementary school and so attracted
comments
from one or two who should perhaps still be confined to the classrooms of
that elementary school? If so, then I apologise, but I'm still interested in
the
elementary mechanisms of electric current, but from a perspective of one who
has experience of much more in-depth paradigms.