Understanding Microscopic Ohm's Law

[ed2288]

Homework Statement

Explain the terms used in the microscopic version of Ohm's Law

Homework Equations

j=oE

The Attempt at a Solution

Well I know what we have here is the current density within a conductor is equal to its conductivity multiplied by an 'E-field'. But what is this E-field? Is it an external field that acts upon the wire? But if this is the case will the electrons in the conductor not just move in a few microseconds to go back into equilibrium meaning j=0. You could act on it with an varying field but then how would the calculation work out?
Or is E the field inside the conductor caused by the current density?
Thanks

 

[LowlyPion]

Homework Statement

Explain the terms used in the microscopic version of Ohm's Law

Homework Equations

j=oE

The Attempt at a Solution

Well I know what we have here is the current density within a conductor is equal to its conductivity multiplied by an 'E-field'. But what is this E-field? Is it an external field that acts upon the wire? But if this is the case will the electrons in the conductor not just move in a few microseconds to go back into equilibrium meaning j=0. You could act on it with an varying field but then how would the calculation work out?
Or is E the field inside the conductor caused by the current density?
Thanks

Maybe this helps?
http://hyperphysics.phy-astr.gsu.edu/HBASE/electric/ohmmic.html

 

[ed2288]

Hmmm I guess I've spent so long doing electrostatics that I'm struggling a bit with the intuition of currents.
So from the link above, am I right in thinking the E field is from within the wire caused by a potential difference from a power source?