EskWIRED@[EMAIL PROTECTED]
wrote:
> I'm wondering how one can squeeze more current through a given diameter
> wire by means of increasing the voltage.
E=IR so assuming the R is fixed, the bigger the E the bigger the I.
> I'm wondering a bunch of other stuff too, but the answer to this
question
> seems basic to my eventual understanding of other questions.
>
> "More current" means that more coulombs of charge pass by a given point
> per unit of time. I take this to mean that more electrons flow past the
> point.
Yes.
> If more electrons pass by the point per unit of time, does this mean
that
> the velocity of the electrons is greater at higher voltages, all other
> things being equal? Is the means of getting more electrons through a
> given wire to increase the velocity of the electrons by means of
> increasing the voltage?
>
> If so, then how fast do electrons travel?
This is a bit complicated, but not very fast. See:
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmmic.html
> I (think I) understand that the electrons do not necessarily pass
through
> the entire length of the wire, but instead, they travel between adjacent
> copper atoms. When one atom near the source gets extra electrons, it
> p***** some electrons to its neighboring atom. This propogates down the
> wire from one end to the other, until eventually, the current reaches
the
> load at the other end.
>
> And am I correct that at higher voltages, this process happens more
> quickly? If one had a really long wire, could the time difference be
> noticible and significant?
>
> So how fast does this effect propogate down the length of the wire? And
> is velocity of travel the mechanism that allows more electrons to "pass
> through" a thin wire at higher voltage per unit of time?
See the above link.
> OK, so that is my basic question, and I guess it assumes DC voltages.
Is
> that true?
Doesn't matter.
> Taking it one step further, ISTM that with AC, the electons starting at
> the source might not get too far down the wire before polarity changes.
> Here in North America, we switch polarity 60 times a second.
>
> So are the same electrons going back and forth, back and forth, along
the
> same physical chunk of wire at AC voltages?
Basically.
> AND - what happens when we use low voltage and high frequency?
Nothing much different.
> Specifically, what would happen if the switching frequency is
> significantly quicker than the time required for the voltage change to
> propogate all the way down the wire from the generator to the load?
Does
> the transmission system suffer weird phase problems?
As the frequency increases the inductance of the wire start to become
a significant reactance and the current and voltage are no longer in
phase.
> And am I starting to figure out the term "Power Factor" using this line
of
> reasoning, or am I going in weird circles, and beginning my reasoning
> process with defective premises?
Power factor is a measure of the reactance of a system.
See:
http://en.wikipedia.org/wiki/Power_factor
--
Jim Pennino
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