> Hi Mario, >=20 > The link Rubin posted explains the situation quite well. I'm not sure abo= ut why > there's a threashold point where the voltage starts decreasing though. The reason is because the field lines from the electric fields are radiatin= g=20 out from each plate. When they are close together the field lines can be se= en=20 as parallel to each other but when they are moved apart you can look on eac= h=20 plate as a point where the lines are radiating in all directions. The field= =20 line density from one plate will be lower on the other plate the further ap= art=20 they are. I don't think there is a sharp threshold where the voltage starts to decrea= se=20 though. The energy put into a capacitor with an insulating dielectric when charging= it=20 is actually the work required to polarize the dielectic between the plates.= The=20 more it gets polarized the more it resists even more polarization which is = why=20 the charge and discharge curves looks the way they do. The equivalent component for a capacitor in a water circuit can be a barrel= =20 with a flexible membrane in the middle. You can not flex the membrane with= =20 water pressure (voltage) on one side witout having somewhere for the water = to=20 go on the other side. When both ends are connected to pipes (of the same=20 circuit) and water pressure is applied over it, the membrane will flex and= =20 store energy. When the pressure is removed (with the circuit still closed) = the=20 membrane will go back to neutral and will push back water while doing so. I= t is=20 also clear here that no water from one side is actually passing the membran= e to=20 the other side so DC currents are blocked. AC currents will push the membra= ne=20 back and forth, affecting the water on both sides. But I can not quite see = how=20 the moved plates in an electric circuit would work with this analogy. /Ruben --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .