View 3D representations of field lines and equipotential surfaces fo one or two charges.  You can display the full surfaces or cut one half of the surfaces, so you can better look inside.  Note how the field lines and the equipotential surfaces are perpendicular to each other everywhere.

The potential difference between successive eqipotential surfaces is the same.
Red surfaces are at positive potential. Blue surfaces are at negative potential.
The center plane is at zero potential.