The potential gradient at a point in an electric field is the change of potential per unit change of distance in a given direction. In a non-uniform field, the closer the equipotentials are, the greater the potential gradient at right angles to the equipotentials.In a uniform field the equipotentials are equally spaced and parallel so the potential gradient is constant.The electric field strength E=V/d and is directed from positive to negative. The potential gradient is equal to V/d and increases in the opposite direction to the electric field.The electric field strength is the negative of the potential gradient.