This textbook covers the electrical principles syllabuses of the major examining bodies, including that of the City and Guilds of London Institute, Part 2 of the CGLI 232 series craft course and the Electricians' 236 Certificate. Theories are explained with the aid of fully worked examples and there are more than 390 graded exercises for which numerical answers are provided. A complete list of symbols, abbreviations and units is included in the text, along with an introduction to SI units. Each chapter concludes with a summary of the formulae introduced. The volume will also be of benefit to practising craftsmen and technicians anxious to extend their grasp of electrical principles to meet the rapidly expanding requirements of the industry.