The present invention relates to the methods of construction for inductive components of, preferably, ferromagnetic materials such as inductors, chokes, and transformers when used as an integral part of the fabrication of PCB's or FLEX's. In one preferred embodiment, holes (56, 58) are formed through a ferromagnetic substrate (50) and plated with conductive material. The arrangement of these holes, and the subsequent design that ensues, will form the inductive components within the plane of the media in which the device is formed; using the substrate (50) for a magnetic core (90). By using this approach, the inductive components can be miniaturized to physical sizes compatible with the requirements of modern surface mount technology (SMT) for integrated circuitry (IC). This process also allows these components to be fabricated using mass production techniques, thereby avoiding the need to handle discrete devices during the manufacturing process. In another preferred embodiment, a series of thin, concentric high permeability rings (315) are etched on a substrate (330) to provide high permeability transformers and inductors having minimal eddy current effects.