Knowledge of fundamentals is critical to the success of a modern electrical technician, and this book explores direct current (DC) principles and methods as well as the underlying theories and concepts needed for a strong foundation in electrical technology. Readers are introduced to the fundamentals of electricity and DC circuits, including how properties of materials are categorized into conductors, semiconductors, and insulators. In-depth coverage of Ohm's law and its relation to voltage, current, resistance, and power is presented, followed by the theory and practical applications of electrical components connected in series. Later chapters examine DC parallel circuits, DC combination circuits, magnetism and generators, and DC circuit analysis tools that electricians will find invaluable in analyzing and understanding more complex circuits likely to be encountered on the job. Although based on DC circuits, the information supplied in this book will apply to alternating current (AC) circuits as well. This book contains much of the material that forms the foundation of electrical knowledge.