Abstract: Inside a first case outer frame portion as an outer frame of the first case, a plurality of first core pieces and a partition to separate a pair of adjacent first core pieces among the plurality of first core pieces are disposed. The first case has a shape capable of accommodating at least a part of the second core piece. The first case outer frame portion includes a first case accommodating portion as a portion of the first case outer frame portion that is capable of accommodating the plurality of first core pieces, and a first case cover portion to cover a space inside the first case accommodating portion.

Abstract: A coil apparatus includes a coil unit including a coil, a base core that is a first core component, and a core module that is a second core component. The first core component includes a center leg that is a leg around which the coil is wound. The second core component includes a plurality of core segments arranged in a row with gaps between them. The second core component is connected to the leg to form a magnetic path together with the first core component.

Abstract: Inside a first case outer frame portion as an outer frame of the first case, a plurality of first core pieces and a partition to separate a pair of adjacent first core pieces among the plurality of first core pieces are disposed. The first case has a shape capable of accommodating at least a part of the second core piece. The first case outer frame portion includes a first case accommodating portion as a portion of the first case outer frame portion that is capable of accommodating the plurality of first core pieces, and a first case cover portion to cover a space inside the first case accommodating portion.

Abstract: An insulation type step-down converter includes first and second step-down transformers each of which includes an input-side coil and an output-side coil. An intermediate portion of the output-side coil of the first step-down transformer and an intermediate portion of the output-side coil of the second step-down transformer are connected to each other. First, second, third, and fourth rectifier elements are connected in series with first, second, third, and fourth output-side coils, respectively. Smoothing coils are connected to the first to fourth output-side coils. The first, second, third, and fourth rectifier elements are connected such that electric currents flow simultaneously in the first output-side coil and the third output-side coil, and electric currents flow simultaneously in the second output-side coil and the fourth output-side coil in a manner alternating with the electric currents in the first output-side coil and the third output-side coil.

Abstract: An insulation type step-down converter includes first and second step-down transformers each of which includes an input-side coil and an output-side coil. An intermediate portion of the output-side coil of the first step-down transformer and an intermediate portion of the output-side coil of the second step-down transformer are connected to each other. First, second, third, and fourth rectifier elements are connected in series with first, second, third, and fourth output-side coils, respectively. Smoothing coils are connected to the first to fourth output-side coils. The first, second, third, and fourth rectifier elements are connected such that electric currents flow simultaneously in the first output-side coil and the third output-side coil, and electric currents flow simultaneously in the second output-side coil and the fourth output-side coil in a manner alternating with the electric currents in the first output-side coil and the third output-side coil.