The influence of temperature and wavelength on electrical parameters of crystalline silicon solar cell and a solar module are presented. At the experimental stand a thick copper plate protected the solar cell from overheating, the plate working as a radiation heat sink, or also as the cell temperature stabilizer during heating it up to 80degreesC. A decrease of the output power (-0.65%/K), of the fill-factor (-0.2%/K) and of the conversion efficiency (-0.08%/K) of the PV module with the temperature increase has been observed. The spectral characteristic of the open-circuit voltage of the single-crystalline silicon solar cell is also presented. It is shown that the radiation-rate coefficient of the short-circuit current-limit of the solar cell at 28degreesC is 1.2%/(mW/cm(2)). (C) 2002 Elsevier Science Ltd. All rights reserved,