The second edition of this introductory book sets out clearly and concisely the principles of operation of the semiconductor devices that lie at the heart of the microelectronic revolution. The book aims to teach the reader how semiconductor devices are modelled. It begins by providing a firm background in the relevant semiconductor physics. These ideas are then used to construct both circuit models and mathematical models for diodes, bipolar transistors and MOSFETs. It also describes the processes involved in fabricating silicon chips containing these devices. The first edition has already proved a highly useful textbook to first and second year degree students in electrical and electronic engineering, and related disciplines. It is also useful to HND students in similar subject areas, and as supplementary reading for anyone involved in integrated circuit design and fabrication.