In 23 chapters, the book deals with the formation of energy bands in solids; electron emission from solid surfaces; properties of semiconductors; metal-semiconductor contacts; pn junction diodes; rectifiers; voltage multipliers; clipping and clamping circuits; bipolar junction transistors; basic voltage and power amplifiers; feedback in amplifiers; regulated power supplies; sinusoidal oscillators; multivibrators; modulation and demodulation; field-effect transistors; ICs; OP AMPs; active filters; special semiconductor devices such as phototransistor, SCR, triac, diac, UJT, impatt diode, gunn diode, PIN diode, IGBT, etc.; digital circuits and systems; VLSI technology and circuits; CRO; communication systems; television; radar; lasers; fibre optics and holography. Software packages for circuit simulation, namely, Spice and PSpice have been included in an Appendix. Fundamental principles and applications are discussed herein with explanatory diagrams in a clear and concise way. Physical aspects are emphasized; mathematical details are given, when necessary. Many of the problems, review questions, and objective-type questions included in the book are taken from recent examination papers.