  Charge reversal of the planar electrical double layer is studied by means of
a well known integral equations theory. By a numerical analysis, a diagram is
constructed with the onset points of charge reversal in the space of the
fundamental variables of the system. Within this diagram two regimes of charge
reversal are identified, referred to as oscillatory and non oscillatory. We
found that these two regimes can be distinguished through a simple formula.
Furthermore, a symmetry between electrostatic and size correlations in charge
reversal is exhibited. The agreement of our results with other theories and
molecular simulations data is discussed.
