Current and Resistance
Energy and Power 
Think of moving -- "walking", if you like -- through this simple electric circuit while carrying a positive charge. As you move through the battery -- from a to b -- the battery does work on the charge and increases its potential energy. As you move along the conductor from b to c, no work is done so its potential energy remains constant. As you move through the resistor -- from c to d -- the charge does work on the resistor, the resistor becomes warm, and the potential energy of the charge decreases. The charge returns to the battery through the conductor from d to a and no work is done so its potential energy again remains constant.
Mechanical model
(c) Doug Davis, 2002; all rights reserved
Return to ToC