Re: Simple electricity, and yet.....!

On Thu, 16 Nov 2006, Sorcerer wrote:

"Timo A. Nieminen" <timo@xxxxxxxxxxxxxxxxx> wrote:
| On Thu, 16 Nov 2006, xray4abc wrote:
| >
| > Yes. I have always thought that the electric field created by
| > the power source was "pushing" the electrons.
| > It seems that there is something wrong with this picture of the
| > process.
|
| What makes aircraft fly at a constant velocity? Thrust = drag. What makes
| a spaceship travel at constant velocity? Thrust = drag must still be true,
| but drag = 0, therefore, one can conclude what?
|
| You're specifically considering the case of R=0. Why should any force be
| needed to keep the electrons moving?
|
| From a circuit analysis viewpoint, it really is trivial. From a Maxwell
| viewpoint, it's less trivial. If you want it to be an educational problem,
| figure out how Maxwell gives you the circuit theory picture. Just keep in
| mind that circuit theory general treats wires as R=0, while in Maxwell,
| their conductivity is not infinite.

What limits the beam current in a CRT?
Thust equals drag?
Permittivity?
None of the above?
It really is trivial.

What? You don't know the answer? You, the former "electronic engineer,
professionaly", need me to tell you? If you do know, are you so desperate
for attention that you're reduced to trolling on threads about circuit
theory?

It's essentially the same as the the PEC shorting a non-ideal power supply
as asked about by the OP: the current is mostly limited by the power
supply (in this case, the electron gun, its power supply etc). Do you
disagree that the total force on an electron moving at constant velocity
in a CRT is zero?

Despite the similarity between the CRT+circuit, and the PEC+circuit, there
is a fundamental difference: the charge density inside the PEC is zero,
while the charge density in the operating CRT is not, which will
contribute to limiting the current. Show your engineering talent: how
large is this contribution?

If you aren't just pointlessly trolled and really want to discuss physics,
you could continue some of our past discussions that you ran from:

Why do you claim that the field gradient is called the field strength?

What is the phase relationship (in time) between E and B in a
monochromatic plane-polarised plane EM wave in free space?

When is 5 hours earlier than 5 hours later than now?

Is the average magnitude of the velocity of an object that travels at
constant speed from A to B and back to A really equal to 0/0?

Why aren't you willing to discuss a derivation of the Lorentz
transformations?
http://groups.google.com.au/group/sci.physics/msg/07fbb2e45180a599?hl...

Why did you claim in successive posts that (a) Newton's laws don't hold in
any coordinate system, and (b) Newton's laws hold in every coordinate
system?

Now, from your past history, you'll either (a) cut and run,
(b) obsessively reply to my posts, or (c) respond with foul language.
Perhaps (d) all of the above, just as you did last time. The odds of you
actually making an attempt to discuss physics seems remote, from past
performance, but I ask: do you dare?

PS: Some might say that you are cowardly to post the type of
"content" that you post anonymously, but perhaps it is a sign of
consideration for your family, to protect them from being known as your
relatives - with all the associated stigma of possibly-hereditary
deficiency. You, such a sad and sorry example of a great and noble
people, indeed act in a compassionate manner to avoid your stink tainting
the reputation of that great and noble people!

PPS: Aren't I supposed to be a resident of your killfile?

--
Timo
.

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