This chapter provides a comprehensive overview of the key principles underlying PV technology, exploring the fundamental concepts of solar radiation, semiconductor physics, and the intricate mechanisms that facilitate the transformation of sunlight into a usable electrical. This chapter provides a comprehensive overview of the key principles underlying PV technology, exploring the fundamental concepts of solar radiation, semiconductor physics, and the intricate mechanisms that facilitate the transformation of sunlight into a usable electrical. Photovoltaic technology, often abbreviated as PV, represents a revolutionary method of harnessing solar energy and converting it into electricity. At its core, PV relies on the principle of the photovoltaic effect, where certain materials generate an electric current when exposed to sunlight. Solar panels, also called PV panels, are combined into arrays in a PV system. PV systems can also be installed in grid-connected or off-grid (stand-alone) configurations. They use this sunlight to create direct current (DC) electricity through a process called "the photovoltaic effect.