Transformer

A transformer comprising:

• a coil including at least a first substantially flat winding;
• a first magnetic core including a plate, a middle leg provided in a standing manner at the central portion of the plate and outer legs provided in a standing manner at a plurality of corners of the plate, the first magnetic defining, between the middle leg and the outer legs, a winding accommodating portion for accommodating the coil therein;
• and
• a second magnetic core mounted on the first magnetic core;
• wherein a cross-sectional ape of the middle leg is at least partially curved;
• wherein a curved portion of a cross-sectional outer peripheral shape of the middle leg has the shape of an arc formed substantially concentrically with a curved portion of an outer periphery of the winding accommodating portion;
• wherein said outer periphery of the winding accommodating portion is formed so as to be close to or substantially coincide with side portions of an external shape of the first magnetic core, said side portions being defined respectively between the outer legs;
• and
• wherein an area determined by the product of a cross-sectional peripheral length of the middle leg and a thickness of the plate is substantially equal to or greater than a cross-sectional area of the middle leg.

A transformer comprising:

• a coil including at least a first substantially flat winding;
• a first magnetic core including a plate, a middle leg provided in a standing manner at the central portion of the plate and outer legs provided in a standing manner at a plurality of corners of the plate, the first magnetic core defining, between the middle leg and the outer legs, a winding accommodating portion for accommodating the coil therein;
• and
• a second magnetic core mounted on the first magnetic core;
• wherein a cross-sectional shape of the middle leg is at least partially curved;
• wherein a curved portion of a cross-sectional outer peripheral shape of the middle leg has the shape of an arc formed substantially concentrically with a curved portion of an outer periphery of the winding accommodating portion;
• wherein said outer periphery of the winding accommodating portion is formed so as to be close to or substantially coincide with side portions of an external shape of the first magnetic core, said side portions being defined respectively between the outer legs;
• and
• wherein the total sum of cross-sectional areas of the outer legs is substantially equal to or greater than a cross-sectional area of the middle leg.

A transformer comprising:

• a coil including at least a first substantially flat winding;
• a first magnetic core including a plate, a middle leg provided in a standing manner at the central portion of the plate and outer legs provided in a standing maimer at a plurality of corners of the plate, the first magnetic core defining, between the middle leg and the outer legs, a winding accommodating portion for accommodating the coil therein;
• and
• a second magnetic core mounted on the first magnetic core;
• wherein a cross-sectional shape of the middle leg is at least partially curved;
• wherein a curved portion of a cross-sectional outer peripheral shape of the middle leg has the shape of an arc formed substantially concentrically with a curved portion of an outer periphery of the winding accommodating portion;
• wherein said outer periphery of the winding accommodating portion is formed so as to be close to or substantially coincide with side portions of an external shape of the first magnetic core, said side portions being defined respectively between the outer logs;
• and
• wherein the total sum of areas of inwardly facing portions of areas determined by products of cross-sectional peripheral lengths of the corresponding outer legs and a thickness of the plate is substantially equal to or greater than a cross-sectional area of the middle leg.

A transformer comprising:

• a coil which is elongated and at least partially curved in its outer peripheral shape, said coil including at least a first substantially flat winding;
• a first magnetic core including a plate, a middle leg provided in a standing manner at the central portion of the plate and outer legs provided in a standing wanner at a plurality of corners of the plate, the first magnetic core defining, between the middle leg and the outer legs, a winding accommodating portion sized and shaped for accommodating the coil therein;
• and
• a second magnetic core mounted on the first magnetic core;
• wherein an outer periphery of the winding accommodating portion is formed so as to be close to or substantially coincide with side portions of an external shape of the first magnetic core, said side portions being defined respectively between the outer legs.

A transformer comprising:

• a coil including at least a first substantially flat winding;
• a first magnetic core including a plate, a middle leg provided in a standing manner at the central portion of the plate and outer legs provided in a standing manner at a plurality of corners of the plate, the first magnetic core defining, between the middle leg and the outer legs, a winding accommodating portion sized and shaped for accommodating the coil therein;
• and
• a second magnetic core mounted on the first magnetic core;
• wherein a cross-sectional shape of the middle leg is at least partially curved;
• wherein a curved portion of a cross-sectional outer peripheral shape of the middle leg has the shape of an arc formed substantially concentrically with curved portion of an outer periphery of the winding accommodating portion;
• and
• wherein said outer periphery of the winding accommodating portion is fanned so as substantially coincide with and not to project from at least two side portions of an external shape of the first magnetic core, said side portions being defined respectively between the outer legs.