I have a number of questions on how circuits really function - my class just found itself looking at circuit diagrams and voltages without any explanation of the basics of how circuits actually work. 1) How does the concept of electric potential difference between two points, like with a point charge, relate to circuits? How is it possible to have a "potential difference" between one point of a circuit and another, when there is no field between them? I have the same confusion with capacitors - how is there a potential difference (voltage) between the plates of the capacitor? 2) Similarly, how do things like batteries have voltages? Why does attaching a battery to the circuit, having a voltage (applying a potential difference), make everything flow through the circuit to cause it to function?