Electrical potential difference and charge separation

[NeuralDynamics]

Hello,

I am having a hard time trying to build these concepts in my mind. To generate a electrical potential difference I need to separate charges, right? But if I think in a capacitor, the electrical potential (e.g., battery) will charge the capacitor which, in turn, will keep the charges separated. So my question is what comes first: electrical potential difference or charge separation?

 

[Drakkith]

My understanding:

To generate a electrical potential difference I need to separate charges, right?

Not necessarily. A changing magnetic field can generate a voltage (difference in electric potential) and we can generate a changing magnetic field without having to separate charges.

So my question is what comes first: electrical potential difference or charge separation?

In general, neither comes first. Separated charges will generate a voltage and a voltage can cause a separation of charges. You can, of course, look at a specific system, say an uncharged capacitor, and find that a voltage was applied first and then the charges separated, but that's a choice.

 

[berkeman]

To generate a electrical potential difference I need to separate charges, right? But if I think in a capacitor, the electrical potential (e.g., battery) will charge the capacitor which, in turn, will keep the charges separated. So my question is what comes first: electrical potential difference or charge separation?

The way that I prefer to think about it (in terms of cause-and-effect) is that an EMF (electomotive force) of some kind drives a current which creates a separation of charge and the resulting electric field (in your capacitor, for example). The changing magnetic field piercing a coil of wire mentioned by @Drakkith generates such an EMF. So does the battery in your example.