This paper presents a new method to determine the five solar cell parameters of the single diode lumped circuit model. These parameters are usually the saturation current, the series resistance, the ideality factor, the shunt conductance and the photocurrent. This method is based on the measured current-voltage data. The method has been successfully applied to a commercial silicon solar cell, a module and an organic solar cell. (C) 2008 Elsevier Ltd. All rights reserved.