This study investigates the influence of light intensity on the main photoelectric parameters of silicon solar cells. An analysis was carried out on the dependences of short-circuit current, open-circuit voltage, fill factor, and conversion efficiency on the level of incident radiation. The physical processes of charge carrier generation and recombination, which determine the operation of solar cells under different illumination levels, are examined. It was established that the short-circuit current depends linearly on light intensity, whereas the open-circuit voltage follows a logarithmic relationship. It is shown that variations in illumination give rise to nonlinear effects associated with internal losses and the parameters of the p–n junction. The research results make it possible to identify the factors limiting the efficiency of silicon solar cells and may be used in the optimization of photovoltaic systems.