This textbook and exercise book presents the fundamentals of electrical networks in direct and alternating current technology in an easily understandable manner. Many detailed examples accompanied by explanatory text provide confidence in calculating circuits. The 3rd edition has been revised and further improved by incorporating numerous reader requests and suggestions. Additionally, a new section on three-phase systems has been added to the 3rd exercise. The book also offers tasks with detailed solutions online as an additional service. Notably, the compactness of the book and the didactic structure of the material guide the reader step by step from simpler to more complex topics.