Parallel Plate Capacitor
For a parallel plate capacitor, we can pull charge from one plate (leaving a -Q on that plate) and deposit it on the other plate (leaving a +Q on that plate). Because of the charge separation, we have a voltage difference between the plates, DV. The harder we pull (the more voltage across the two plates), the more charge we pull: C = Q /DV. Note that C is NOT CHANGED by either Q or DV; C relates Q and DV!