Nowadays power drives are the essential part almost of all technological processes. Improvement of efficiency and reduction of losses require development of semiconductor switches. It has a particular meaning for the constantly growing market of renewable sources, especially for wind turbines, which demand more powerful semiconductor devices for control, while power of turbines constantly grows. Also at present semiconductor switches are the key component in energy transmission, optimization of generation and network connection. The aim of this book is to make a survey of contemporary semiconductor components, showing difference in structures, advantages, disadvantages and most suitable applications. There is topical information about voltage, frequency and current limits of different switches. The book also tells about future prospects of semiconductor market.