So electric field tells us the force per unit charge that is felt by a test charge at a distance d from a source charge. So it tells us that the closer the test, or other charge, is to the source charge ,the stronger the interaction, and also that the larger the source charge, the stronger the interaction as well. Hence E = F/q = kQsource/d^2 1) What I am having trouble understanding is how the electric field between a parallel plate capacitor is constant? I think part of my misunderstanding comes from the fact that we're not dealing with a single source charge but an electric field created by the interaction between two sources, the positive plate and the negative plate. Is that interaction what makes the electric field constant? 2) Also, while electric field changes with distance from a source charge, in between a parallel plate capacitor, the electric field is constant regardless of where you are in between the capacitor? 3) To add to that, the electric potential decreases as you go from positive to negative plate, yet the electric field doesnt. Normally, a change in electric potential changes the electric field doesnt it?