Abstract: A miniaturized or chip-type HF magnetic-coil arrangement, e.g. a toroidal core transformer, comprising a basic body (1) of plastic material, which is provided with openings for magnetic cores (2), the upper side (10) and the lower side (11) of said basic body (1) including electric conductors (5) and the interior thereof being provided with plated-through holes in openings (16) to which the conductors (5) are connected in such a way that individual turns around the magnetic core are formed, said turns defining windings of coils (6, 7). Moreover, methods are provided, which permit a production of these arrangements in large numbers of pieces.