Core for coil device such as power transformers, choke coils used in switching power supply

摘要

The invention pertains to a core for a coil device of a switching power supply which can avoid accidental breakage of the portion where the core cross-sectional area narrows. When one core segment is rotated 180 degrees about its center axis in the long direction of one leg 2, the projection 51 of one core segment 1A and the projection 52 of another core segment 1B, and the indentation 61 of the one core segment 1A and the indentation 62 of the other core segment 1B are aligned so as to mutually overlap. The characteristics of a coil device can be controlled by the contacting surface areas of both core segment projections or by spacing between the projections. Since the cross- sectional area of each core projection can be made wider, accidental breakage of the core projection does not occur easily.