9.2.1—The potential difference across a component as the energy transferred per

Potential difference V is the energy transferred per coulomb when charge moves between two points: V=energy per charge.

Specify the component and direction of energy transfer. A source supplies energy; a resistor or motor transfers it to other stores.

A 6 V battery supplies 6 J to each coulomb passing through the external circuit ideally.

Potential difference is not current and is not “used up” as charge circulates; components have voltage drops or rises.