I think you basically get the ideas now. The one thing you seem to be struggling with is voltage without current. In terms of the equation for an open circuit V = 0 x infinity. Well 0 x infinity does some weird mathematical stuff where depending on the situation it can be anything.
Remember that voltage is potential energy (keyword potential). Imagine a bucket of water with a closed valve on the bottom. The water has plenty of potential energy, you know it's pushing against the valve, it just can't go anywhere or do anything. That's your potential energy without current.
Originally Posted by JonnyDread
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