An electrical transformer, comprising: a first multilayer printed circuit board having a plurality of first electrically isolated electrical conductor segments (16a, 16b, 16c, 16d) disposed on each one of a plurality of electrically isolated levels of such first multilevel printed circuit board; a second multilayer printed circuit board, disposed over, and in registration with, the first multilevel printed circuit board, such second multilevel printed circuit board having a plurality of second electrically isolated electrical conductor segments (14a, 14b, 14c, 14d, 14e, 14f) disposed on each one of a plurality of electrically isolated levels of such second multilevel printed circuit board; one core having two apertures, or an adjacent pair of toroidal shaped cores (12a', 12b') each having one aperture, each aperture extending between the first and second multilevel printed circuit boards (16, 14);a respective dielectric body (22a, 22b; 22a', 22b') disposed in each aperture, such body having disposed therein a plurality of third electrically isolated electrical conductor segments; and wherein first ends of the third electrically isolated electrical conductor segments are electrically connected to the plurality of first electrically isolated electrical conductor segments (16a, 16b, 16c, 16d) and second ends of the third electrically isolated electrical conductor segments are electrically connected to the plurality of second electrically isolated electrical conductor segments (14a, 14b, 14c, 14d, 14e, 14f); characterised in that a primary winding of the transformer only consists of first ones of the first electrically isolated electrical conductor segments (16a, 16b, 16c, 16d), first ones of the second electrically isolated electrical conductor segment (14a, 14b, 14c, 14d, 14e, 14f), and first ones of the third electrically isolated electrical conductor segments; and a secondary winding ofthe transformer only consists of second ones ofthe first electrically isolated electrical conductor segments (16a, 16b, 16c, 16d), second ones of the second electrically isolated electrical conductor segments (14a, 14b, 14c, 14d, 14e, 14f), and second ones ofthe third electrically isolated electrical conductor segments. a first multilayer printed circuit board having a plurality of first electrically isolated electrical conductor segments (16a, 16b, 16c, 16d) disposed on each one of a plurality of electrically isolated levels of such first multilevel printed circuit board; a second multilayer printed circuit board, disposed over, and in registration with, the first multilevel printed circuit board, such second multilevel printed circuit board having a plurality of second electrically isolated electrical conductor segments (14a, 14b, 14c, 14d, 14e, 14f) disposed on each one of a plurality of electrically isolated levels of such second multilevel printed circuit board; one core having two apertures, or an adjacent pair of toroidal shaped cores (12a', 12b') each having one aperture, each aperture extending between the first and second multilevel printed circuit boards (16, 14);a respective dielectric body (22a, 22b; 22a', 22b') disposed in each aperture, such body having disposed therein a plurality of third electrically isolated electrical conductor segments; and wherein first ends of the third electrically isolated electrical conductor segments are electrically connected to the plurality of first electrically isolated electrical conductor segments (16a, 16b, 16c, 16d) and second ends of the third electrically isolated electrical conductor segments are electrically connected to the plurality of second electrically isolated electrical conductor segments (14a, 14b, 14c, 14d, 14e, 14f);