An induction device has an elongated core made of two or more uniform ferromagnetic spaced-apart toroids. A first winding around the core creates an inductor. When the induction device includes a second winding, a transformer is created. The transformer acts as a powercord transformer when the exposed ends of one winding are available at one end of the elongated core for connection to a source of alternating current and the exposed ends of the other winding are available at the other end of the core for connection to a load. An inductor with a single-turn winding can be constructed by first forming the core by stacking two or more ferromagnetic toroids end-to-end and spaced apart, then threading two wires through the core center and placing two wires outside the core and connecting the ends of the wires to create the winding. A transformer can be constructed by first following the steps to create an inductor. A second winding is then created in a similar manner as the first winding.