This textbook for courses in electrical principles, circuit theory, and electrical technology takes students from the fundamentals of the subject up to and including first degree level. The coverage is ideal for those studying engineering for the first time as part of BTEC National and other pre-degree vocational courses, especially where progression to higher levels of study is likely, as well as Higher Nationals, Foundation Degrees and first year undergraduate modules. Now in its third edition, this best-selling textbook has been updated with developments in key areas such as semiconductor diodes, transistors, batteries and fuel cells, along with brand new material on ABCD parameters and Fouriers Analysis. Greater emphasis is also placed on showing how the theory covered is applied in real-life engineering practice. In addition, the text has been restructured and exercises now appear at regular intervals so that learning progress can be checked throughout.