An alternative signal appearing at the photovoltaic module output under chopped illumination has been shown to have an information allowing to recover both dark and illuminated I-V characteristics of the individual cells, provided the module circuit is in the Galvanostatic mode. The important cell parameters such as voltage drop, open circuit voltage, short circuit current and ideality factor are evaluated experimentally without the disassembly of the module. The approach may be useful for the control of the quality of cells in the already encapsulated or single-substrate integrated modules. (C) 2002 Elsevier Science B.V. All rights reserved.