Re: Basic Question

On Sep 5, 5:50 am, EskWI...@xxxxxxxxxxxxxxxxxxx wrote:
In sci.physics.electromag, j...@xxxxxxxxxxxxxxxxxxxx wrote:
EskWI...@xxxxxxxxxxxxxxxxxxx wrote:

Ummm....using any wire of any thickness and a given resistance per unit of
length, why is it that more voltage will yield more current? Is it a
matter of velocity of electron flow?
Because E=IR which is basic Ohm's Law.

That I know. The question is why.

I'm wondering how one can squeeze more current through a given
diameter
wire by means of increasing the voltage.

I'm wondering how one can squeeze more current through a given
diameter
wire by means of increasing the voltage.

Why, for example, does one needs to use thicker wires on the low side of a
transformer, while on the high side, one can use thinner wires?
Because P=I^2 R and P=EI.

That I already know.





The power in and power out of a transformer (ignoring losses) are equal,
but the voltages aren't, which is normally why one is using a transformer
in the first place.
So, for a fixed amount of power, the current is higher on the low side,
hence thicker wire to carry that current and less loss in the winding
due to I^2 R losses.
On the high side, keeping in mind the power is fixed, the current is
lower hence you don't need wire as thick as the low side.
I'm not asking to be told that the resistance of the thick wire is lower,
so by applyng Ohm's law, we see that....

Instead, I'm asking what is going on at a particle level. And
Ohm's law works at the macro level and answers the questions.
Analysis at the particle level doesn't really address the questions
you asked.
additionally, as a corollary question, I'm asking whether the associated
magnetic field propogates down the length of the wire at a greater
velocity at higher voltage.
No.
The magnitude of the magnetic field is a function of current.
The magnetic field propogates at c.

I thought that electromagnetic fields propogated at C only in free space.
Doesn't a wire provide significant resistance?

Are you saying that low voltage electricity travels at the same velocity
as high voltage electicity?

--
The whole problem with the world is that fools and fanatics are always so
certain of themselves, but wiser people so full of doubts.
-- Bertrand Russel- Hide quoted text -

- Show quoted text -

I'm wondering how one can squeeze more current through a given
diameter
wire by means of increasing the voltage.


this is why I sugested carbon wire becuase of the wires effeicincy
less power is reqiured to move electrons through the medium.

All carbon nanotube wire is a very good thermal conductors along the
tube, exhibiting a property known as "ballistic conduction," but good
insulators laterally to the tube axis. It is predicted that carbon
nanotubes will be able to transmit up to 6000 watts per meter per
kelvin at room temperature; compare this to copper, a metal well-known
for its good thermal conductivity, which only transmits 385 W·m-1·K-1.
The temperature stability of carbon nanotubes is estimated to be up to
2800 degrees Celsius in vacuum and about 750 degrees Celsius in air.


.

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