I have written for the beginning student who pursuing a technical degree in Electronics and communication Engineering (B.E, B.Tech, M.Sc, Diploma , AMIE) . The focus on absolutely essential knowledge for technicians, electronics and electrical engineers focus on real-world applications of these basic concepts makes it ideal for today’s technology students. In covering the fundamentals of electricity and electronics, this text focuses on essential topics Atomic structure and energy levels, Concept of insulators, conductors and semiconductors, Atomic structure of Ge and Si, Covalent bonding, Intrinsic and extrinsic semiconductor , P and N impurities , doping, conductivity of semiconductor, energy level diagram and minority and majority carriers etc in depth.