An electric transformer comprising a coil made of at least one winding, the winding being made of a wire comprising a first section, a second section and a middle section between the first and the second sections, the first section forming a first spiral around an axis (Z) and the second section forming a second spiral around the axis, the first and second spirals being located in two separate planes perpendicular to the axis, an inner end of the first spiral, respectively the second spiral, located near the axis being near the middle section of the winding and an outer end of the first spiral, respectively the second spiral, located away from the axis being near a free end of the winding, the first spiral and the second spiral turning around the axis in opposite directions.

An electric transformer comprising a primary coil, a secondary coil and a first magnetic circuit, the first magnetic circuit comprising at least a first limb and a second limb, the primary coil being wound around the first limb of the first magnetic circuit and the secondary coil being wound around the first limb or the second limb of the first magnetic circuit, wherein the electric transformer further comprises a second magnetic circuit acting as a component for setting a total impedance of the electric transformer at a predetermined value, the second magnetic circuit comprising at least a third limb, only one coil among the primary coil and the secondary coil being wound around the third limb of the second magnetic circuit, the second magnetic circuit being independent of the first magnetic circuit.

A core component is made of a sintered body of an inorganic powder, in which the core component includes a columnar winding portion and a flange portion integrally formed with the columnar winding portion at both axial ends of the columnar winding portion, in which when observed in a cross section perpendicular to an axial direction, a surface layer portion of the columnar winding portion and a surface layer portion of the flange portion have a void occupancy area smaller than a void occupancy area of an inside of the columnar winding portion and of an inside of the flange portion, respectively.

A magnetic device comprises two base portions and magnetic pillars, wherein each of the two base portions has a first surface and the two first surfaces are faced to each other, and the magnetic pillars are disposed between the two first surfaces along a first direction, wherein, in the first direction, two of the magnetic pillars located at the outermost side of the base portion are a first corner pillar and a second corner pillar respectively, n of the magnetic pillars having the same cross-sectional area and located at the center position of the base portion are n center pillars, and cross-sectional area of the magnetic pillars are gradually increased from the first corner pillar to the center pillar closest to the first corner pillar, and from the second corner pillar to the center pillar closest to the second corner pillar.

A transformer includes two first cores, a primary winding and a secondary winding. The secondary winding has a first section and a second section. The first section has a first outlet end, a second outlet end, and a first connection end, wherein the first outlet end and the second outlet end are located at a side of the first section, the first connection end is located at an opposite side of the first section. The second section has a third outlet end, a fourth outlet end, and a second connection end. The third outlet end and the fourth outlet end are located at a side of the second section, and the second connection end is located at an opposite side of the second section. A portion of the primary winding is located between the first section and the second section of the secondary winding.

An inductor component includes a multilayer body including a magnetic layer; an inductor wiring disposed inside the multilayer body; and an external terminal exposed from the multilayer body. The multilayer body or the external terminal has an overlapping region disposed on the inductor wiring and a non-overlapping region not in contact with the inductor wiring, and reflection spectra of the overlapping region is different from reflection spectra of the non-overlapping region when irradiated with light having a prescribed wavelength from an outer surface side.

An inductor structure includes a first inductor and a second inductor. A first portion of the first inductor is disposed on a first layer and a second portion of the first inductor is disposed on a second layer. A first portion of the second inductor is disposed on the first layer and a second portion of the second inductor is disposed on the second layer. The first portion of the first inductor and the second portion of the second inductor at least partially overlap. The second portion of the first inductor and the first portion of the second inductor at least partially overlap.

An isolated switch-mode power supply includes at least one input, at least one output, and a power circuit coupled between the at least one input and the at least one output for converting an input voltage or current to an output voltage or current. The power circuit includes a transformer having one or more primary windings, one or more secondary windings, an electrical insulator, and a core magnetically coupling the one or more primary windings and the one or more secondary windings. Upper portions of the primary and secondary windings are covered with the electrical insulator. Other example switchmode power supplies, transformers, magnetic chokes and methods are also disclosed.

A coil component includes: a core part including: a winding shaft; and a planar flange part provided at an axial-direction end of the winding shaft, and having a groove part provided on an exterior face thereof where a lead part led out from a conductor wound around the winding shaft into the groove part, wherein the flange part has a first recessed part provided on a first side face intersecting with the long axis of the groove part and communicated with the groove part, wherein the area of a cross section, taken in a direction parallel with the first side face, of the first recessed part, is greater than the area of a cross section, taken in a direction parallel with the first side face.

A reactor that includes a coil having a wound portion; a magnetic core; a holding member provided at both ends of the wound portion; a mold resin by which the coil and the holding member are integrated into one piece; a casing that houses an assembly that includes the coil, the magnetic core, and the holding member; and a potting resin that fills up the casing to seal at least a part of the assembly.