The invention relates to a transformer (10, 10') with a core (11) which has a center piece (11a) with a first and a second flange (11b, 11c), in which a first and a second winding (12, 13) of the transformer (10, 10') are wound on the center piece (11a).To produce a transformer as compact as possible which allows simple adaptation to limit leakage currents, it is proposed that the winding end pieces (12a, 12b) of the first winding (12) guided out of the winding body are guided through at least one recess in the first flange (11b) and that winding end pieces (15a, 15b) of the second winding (13) guided out of the winding body are provided which form at least partly loose line ends. Alternatively, the winding end pieces (12a, 12b) of the first winding (12) guided out of the winding body are guided immediately about the edge of the first flange (11b) and connected with connecting elements (14a, 14b) which are arranged on the side of the first flange (11b) opposite the center piece (11a).
The present invention discloses that a primary and a secondary winding coil are respectively wound around the core and are separated by an insulating layer; and the secondary winding coil has a winding portion wound around the core through at least a circle to define two winding terminals, wherein each winding terminal of the winding portion is connected with an extending section extended to the outside of the transformer and is connected with an electricity connecting section at the rear end thereof. The electricity connecting section has plural pins electrically welded on a circuit board, thereby the extending section that is connected with a rectification switch and increases the contact areas with the air for achieving a heat-dispersing effect and the electricity connecting section are crossing connected between the secondary winding coil and the circuit board to save the space on the circuit board for arranging the secondary winding coil.
A reduced cost energy transfer element for power converter circuits. In one embodiment, an energy transfer element according to an embodiment of the present invention includes a magnetic element having an external surface with at least a first winding and a second winding wound around the external surface of the magnetic element without a bobbin. As such, energy to be received from a power converter circuit input is to be transferred from the first winding to the second winding through a magnetic coupling provided by the magnetic element to a power converter circuit output.
