So I am having some trouble conceptualizing potential difference, and how to calculate it without integrating the E-Field. My problem is how exactly would you calculate the potential difference between the two plates of a capacitor. When a capacitor is charged up with a battery of voltage V, the voltage between the plates also increases to V. However, I have no idea why that is, and no idea how you could calculate the potential difference between them. I am also wondering how you could calculate the potential difference between two known point charges. I am aware of Q = CV and all the other equations for capacitors, I just dont understand the reasoning behind V = Q/C etc.