Ok my cognitive barrier is this: All the videos I watched about "what is voltage" explains it pretty much this way:
So there is an electric field which causes electrically charged objects experience force when put in that electric field. So when you place for example a positively charged object in an electric field, this object will have an electric potential energy. Any two points in the field are associated with electric potential, which is the difference in electric potential energy per unit charge between those two points. This is voltage.
Up to this point - all great. But now they jump to explain that "A battery of - for example, 9V - means that the difference in electric potential between its two terminals is 9 Joules per Coulomb.
I don't quite get how this scenario of 2 charged plates creating a field applies to a battery:
- With the 2 charged plates, we are talking about 2 points in an electric field. If you place a positively (or negatively) charged object in that region, it will experience force hence will have a potential energy. With the battery - you need a conducting material.
- As far as I know (which could be wrong) - in the battery - the two terminals are the positively and negatively charged objects (like the plates), so, they are not comparable with just 2 points in a field created by the two plates...?
I think that basically what I don't understand is how this explanation of voltage with the context of 2 points in a field having a potential difference between them apply to electrical current.