Question:
What is the direction of electron flow on different metals
and where can I find a chart of them? For example - It is my
understanding that electrons flow in a straight line on silver and
steel but spiral around a copper conductor. What is the direction of
flow around tin or other metals?
Replies:
Ray
For direct currents:
Currents in a metal induced by an electric field flow
From the positive pole to the negative pole for positive current
From the negative pole to the positive pole for electron current.
It just depends on how you consider if current is negative or positive
charges.
The results are the same in the end.
For direct current in metals, the path is direct from one pole of the
electric field to the other,
The electric field being induced by a voltage potential.
Please refer to the following URL for more detailed information:
http://en.wikipedia.org/wiki/Metal
A different effect occurs for alternating currents:
It is called the skin effect.
In short,
Skin effect is the tendency of an alternating electric current (AC) to
distribute itself within a conductor so that the current density near the
surface of the conductor is greater than that at its core. That is, the
electric current tends to flow at the "skin" of the conductor, at an average
depth called the skin depth. The skin effect causes the effective resistance
of the conductor to increase with the frequency of the current because much
of the conductor does little. Skin effect is due to eddy currents set up by
the AC current. At 60 Hz in copper, skin depth is about 8.5 mm. At high
frequencies skin depth is much smaller.
Methods to minimize skin effect include using specially woven wire and using
hollow pipe-shaped conductors.
Please see the following URL for more details.
http://en.wikipedia.org/wiki/Skin_effect
You should also read about eddy currents at:
http://en.wikipedia.org/wiki/Eddy_current
But in general, current passes through metals in a uniform manner.
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