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This textbook is a collection of the essential rules and principles to help with the understanding of the basics of electric circuits and to provide the proper background to build up a deeper knowledge of practical engineering. The main topics are the fundamental principles and theories in electromagnetic fields and electric circuits upon which all branches of electrical engineering are built. In order to give an overview of electricity, taking into consideration the huge body of knowledge and practical experience, the choice of subjects has been selective. This collection of the essential parts of electricity is based on the author´s higher educational experience and covers the following topics. (1) Basic overview of theories in electromagnetic fields. (2) Fundamental principles and definitions important for analysing electric circuits. (3) Theorems in electric circuits. (4) Fundamentals of AC circuits. (5) Overview of three-phase networks. (6) Introduction to the two-port network analysis. (7) DC transient analysis. This collection of circuit theories is an excellent starting point for the fundamentals of any field of engineering.

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The authors, István Gyurcsek and György Elmer, are electrical engineers with years of experience in higher education and industrial engineering. Their major achievements include the execution of a number of large international R&D projects, several professional publications, patents and textbooks on the subjects of ICT and electrical engineering.

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