DC magnetizing effect in the toroidal core

An effective method to give dc magnetomotive force to the toroidal core in its circumferential direction without using the dc winding is presented. This method is based on the phenomenon that dc m.m.f. appears in the circumferential direction of the tape-wound core, by applying the radial magnetic field to the core from its center. The principle of this phenomenon is made clear by FEM. Several experiments are made to demonstrate features of this phenomenon. As typical examples, applications to the voltage standard of the switching regulator and to the displacement transducer which can detect less than 1μm are reported.