Considering a charge moving down a wire, the electric field does work on the charges. The work done by the electric field can have two outcomes: it can increase the kinetic energy of the charge carriers themselves, or it can be dissipated as heat or other energy forms. I understand that the potential difference between two points is the difference in the electrical potential values which makes the electrons move. However, this is clearly distinct from what we can measure with a voltmeter across these two points, as we will not measure an energy difference for the stored energy that became the kinetic energy for the electrons.
I realise that when the current is constant (kinetic energy of electrons not changing), the voltmeter measurement will be the same as the difference in electric field potential between the two points. For any direct current circuit, the time it takes for the drift velocity/constant current to be reached is negligible so we can assume the voltmeter measure the exact potential difference.
My questions are:
is there a difference between potential difference & voltage? I am thinking that maybe potential difference refers to the actual difference in potential and voltage is the potential difference minus the amount of energy that goes into increasing the kinetic energy of the electrons per unit charge. Therefore voltage would be what we measure with a voltmeter.
my second question is, how this would work for alternating current circuits. Surely then as the kinetic energy of the electrons keeps changing the voltages would not be reflective of the potential difference?
Hope my question makes some sort of sense...