A resonant high current density transformer including two cores that are abut against each other with their first and second side posts on two sides thereof. A first bobbin envelops the first side posts on the same side of the two cores. A side plate is provided on either end of the first bobbin. The space between the two side plates is divided into two coil slots with a spacer, and at least a wire is wound in each coil slot to form a primary winding. A further second bobbin envelops the second side posts on the same side of the two cores. The outer periphery of the second bobbin is divided into two winding regions by another spacer, and a metal plate envelops each of the winding regions to form a secondary winding. A bobbin mount is disposed at the external flank of the second bobbin with a barrier plate at a side thereof for separating the first and the second bobbins. An insulating separating cover is provided on a side of the first bobbin closer to the bobbin mount, and the two ends of the separating cove
