This book aims to provide up-to-date and comprehensive coverage of the electrical principles required in vocational courses. The chapter on semiconductors has been expanded to include field effect transistors and integrated circuits. It has a new chapter on electronic systems, covering the principles of amplifier systems, equivalent circuits, feedback amplifiers, operational amplifiers and logic gates. The book is suitable for BTEC National Diploma/Certificate courses in electrical engineering, electronics, telecommunications and related subjects. It can also be used for CGLI electrical/electronic engineering courses. An ELBS/LPBB edition is available.