# Formation of surface charge densities on wires in simple DC circuits

Currently using resources like:
http://www.matterandinteractions.org/Content/Articles/circuit.pdf [Broken]
http://www.phy-astr.gsu.edu/cymbalyuk/Lecture16.pdf [Broken]

I don't seem to understand why the surface charge densities shown in the pictures are stable. I understand that the densities shown create constant electric fields which drive the current, but not why the surface charges themselves are not subjected to movement.

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Jano L.
Gold Member
They may move slowly along the surface. The only requirement is that there is always some charge to produce the electric field in the wire, and to do that, they do not need to be static.

1 person
They may move slowly along the surface. The only requirement is that there is always some charge to produce the electric field in the wire, and to do that, they do not need to be static.
Oh ok, I think I understand. So is the charge distribution at any particular time representative of the electric field at those positions? I.e. in areas of high charge distribution is there a lesser electric field and areas of low charge distribution a greater electric field (electric field operating on surface charges NOT the inside ones in the wire). What I am getting at is: that there is less likely to be more charges at areas of high electric field, etc.

Jano L.
Gold Member
I.e. in areas of high charge distribution is there a lesser electric field and areas of low charge distribution a greater electric field
I think it is the opposite; in order to produce higher electric field in the metal point P, there has to be more charges close to this point P on the surface.

sophiecentaur