Inductive components play a key role in the development of power supplies, inverters, and other power electronic systems. This textbook focuses intensively on the calculation of the parasitic properties of coils and transformers, depending on the selected core (geometry and material), winding material (round wire, litz wire, foil), and internal structure, i.e., the positioning of the windings in the winding window. Key topics include the various loss mechanisms in the core and winding, the inductive and capacitive couplings, as well as the EMC behavior of these inductive components.