Patent ID: 7091817

Claim:
A planar transformer comprising a ferrite core, at least one primary coil and at least one secondary coil, which can be connected on a printed circuit board, and a coil former with a casing surface, the coil former enclosing part of the ferrite core and carrying at least one secondary coil, wherein each of the secondary coils carried by the coil former is formed by at least one metal winding sheet, which is open on one side, and the primary coil comprising at least one wound conductor wire, the coil former having two walls, which perpendicularly adjoin the casing surface, run in the peripheral direction and together with the casing surface form a winding chamber for the primary coil that is open outward, and in that at least one of the walls has on a side averted from the winding chamber in each case two guiding slots, it being possible for at least one of the winding sheets to be inserted into the guiding slots and to be connected to the printed circuit board.