The variation of current intensity with pressure, at constant voltage, (I-p characteristics), was obtained for planar magnetron discharges in neon, krypton, and xenon on a copper target. The analysis of those curves confirms that an equation of the same type as the one recently obtained by the authors for an argon-copper discharge is an adequate relation to describe the dependence of Current intensity on pressure and voltage for planar magnetron discharges in rare gases. That equation accounts for a bimodal behavior corresponding to the sum of a "magnetron term" and a "diode term." (C) 2004 American Vacuum Society.