This paper talks about the effect of shading on photovoltaic modules due to the passage of nearby objects such as: antennas, trees, chimneys, buildings, etc. In addition to giving a brief analysis on the performance of the same by the effect of shadows because the solar cells allow the passage of current under lighting conditions. In this publication different measurements were made where the area of the cell remains with less illumination, in the same way, I-V curves are shown for different dimensions of shadow, showing the changes that are presented to give a better demonstration of the electrical characteristics of the cells. A small study of unit cells in series and parallel with partial shading is also added to give more detail to the variabilities that occur due to lack of illumination in the modules. Finally, it is important to emphasize that this work was done on an experimental basis to show true measurements that properly demonstrate the effect of shading on photovoltaic cells.