# Drift velocity - when are they done drifting?

Typical drift velocities for electrons in, say, a conducting wire are on the order of $10^{-5}$ m/s. This is not the rate that the signal travel, of course, but the net flow of electrons.

As I understand it, the voltage in the wire causes the electrons to accelerate in a certain direction, which shifts the momentum spectrum to one side. Collisions with positive ions cause the electrons to change their momentum as well.

The point is, if you add up all the accelerating and shifting of momentum spectra and colliding with positive ions, you get a net flow of electrons which can be expressed as $$\vec{v}_{drift} = \frac{ \vec{J} }{nq}$$ with $\vec{J}$ as current density, and n and q as number and current density.

If this is the case, then it seems like eventually (albeit a long eventually), all of the electrons will accumulate at one side, and the signal would be unable propagate.

In this really what would happen?

• The charges move around a loop. – Farcher Oct 30 '16 at 17:08