This text aims to provide an understanding of the basic principles of electronics related to the communication control & computer systems which affect life. Practical applications of the subject are considered throughout & actual devices & their uses are described to encourage the reader to do" some electronics. Mathematical requirements have been kept to a minimum. The book is not based on any single syllabus but is suitable for students taking BTEC units Electronics NII & NIII City & Guilds Electronics Servicing (course 2240) GCSE & ALevel course & short courses in further & higher education. This second chapter has been updated with additions to certain chapters particularly those on digital systems & computing."