Electricity 1 helps the student achieve a basic understanding of electrical theory and its application to devices, circuits, and materials. The knowledge obtained by a study of this text permits the student to progress to further study. It should be realized that both the development of the subject of electricity and the study of the subject are continuing processes. The electrical industry constantly introduces new and improved devise and materials, which in turn often lead to changes in installation techniques. Electrical codes undergo periodic revisions to upgrade safety and quality in electrical installations.