This book presents the basic concepts of electronic devices and circuits in a simple manner. A number of design and analytic numerical problems have been included to help the student understand the application of the concepts clearly. The main topics covered in the book include semiconductor diodes and their application in rectifiers and voltage regulators; transistors, their configurations and application in amplifier and oscillator circuits; Operational amplifiers and their applications; number systems and fundamentals of analog communication circuits and basic transducers. The book will be useful for the first year course in Engineering.