In this chapter, an overview of photovoltaic (PV) technology is presented. Semiconductors form the basis of a PV cell. Starting from an introduction of semiconductor physics, detailed modeling and operational characteristics of PV system are provided. To extract the maximum power from a PV system, various maximum power point tracking algorithms need to be implemented. A few of such algorithms are discussed in brief. Shading, either full or partial, affects the operation of a PV system to a large extent. The impact of shading and mitigation techniques is described in this work. Major emphasis is given to control of PV systems. Different modes of operation and philosophies of control of a PV system are also discussed. Operation below the maximum power and power sharing concepts in a microgrid are discussed at the end. The theory is described by numerical and graphical examples throughout the chapter. © 2016 Elsevier Inc.