This book discusses photovoltaics and details the modelling of photovoltaics systems. The author demonstrates this modelling using Matlab/Simulink and also Proteus (ISIS). The author first shows the employment of Matlab/Simulink for modelling of a photovoltaic (PV) module. He then presents a Matlab/Simulink and experimental studies of shading effect on a photovoltaic array. He goes on to show modelling of novel architecture of PV generator based on a-Si: H/c-Si materials and using solar tracker for partial shading. Finally, he details the real-time of a PV system using an Arduino Uno Card.