Hi. I know how to work with potentials and how to solve problems involving them, but what exactly does it mean that we connect something (say, a spherical shell) to a potential V0? What is "actually" happening? My guess is charges are "pumped" from some source to the material until an electric field in the radial direction is created such that the potential difference between the shell and infinity is V0. But if I were asked to calculate the expression for that electric field I would be at a loss, since I cant use E = -∇V. Thank you for your time.