This paper presents an investigation study of solar panel characteristics under uniform solar irradiance and partial shading conditions (PSC) and an analysis for determining the global maximum power point (GMPP) of solar panel. As known, solar panel experiences multiple maximum power points (MPPs) if PSC occurs. Therefore, MPP tracking (MPPT) becomes harder compared with the uniform irradiance condition in case of usage of classical algorithms. In this regard, analyzes for uniform and PSC are made by using perturb and observe (P&O) algorithm in this study. By performing several simulations, behavior of the GMPP under PSC is aimed to detect accurately. With the help of these simulations, range of voltage (region for GMPP) can be estimated as user defined accuracy.