My friend has this thing that looks like a pack of gum and when you grab and pull the piece sticking out it shocks you, it isn't really that powerful, but I want to make a better one. I opened it up and it is a fairly simple device. It has three button cell batteries with the negative side attached to a contact plate and the positive attached to the capacitor. The capacitor has the neg attached to the same plate as the batteries negative. The only problem is that the positive plate is attached to a third prong on the capacitor. Why would a capacitor have three? I have tried charging a 220 uf cap. with a 9v battery, but it doesn't deliver any shock even though it should be higher voltage and capacitance than the original device.