Abstract: An inverter transformer includes a coil unit and a transformer core unit. The coil unit includes a bobbin formed with a core-receiving compartment, and a plurality of windings including two primary windings and two secondary windings wound around the bobbin. The secondary windings are disposed adjacent to each other and are coupled electromagnetically and respectively to the primary windings. The transformer core unit includes an internal core part that extends into the core-receiving compartment of the bobbin, and an external core part that forms a magnetic circuit path with the internal core part. The external core part includes a main segment extending externally at one side of the bobbin and a protrusion segment extending from the main segment toward a portion of the bobbin that is disposed between the secondary windings.

Abstract: A method for adjusting mutual inductance is adapted for use in a transformer including a main core and two windings that are wound on the main core and that have the mutual inductance established therebetween. The method includes the steps of: (A) disposing an adjusting core between the windings and adjacent to the main core, the adjusting core having a cross-sectional area smaller than that of the main core; and (B) without resulting in division of flux of the mutual inductance established between the windings, and division of an exciting magnetic flux into a plurality of independent magnetic paths, adjusting position of the adjusting core relative to the main core to vary the mutual inductance established between the two windings.

Abstract: An inverter transformer includes a coil unit including a bobbin and a plurality of windings, and a transformer core unit. The bobbin is formed with a core-receiving compartment, and includes first, second and third coil winding portions. The windings are wound around the first, second and third coil winding portions, respectively. The transformer core unit has an internal core part that extends into the core-receiving compartment.