Transformer

A transformer, comprising:

• a winding frame, having a winding portion, a first baffle, a second baffle, and a terminal socket, wherein the winding portion has a through hole, the first baffle and the second baffle are respectively and horizontally extended from two opposite ends of the winding portion, and the terminal socket is connected to the second baffle;
• a first coil, wound on the winding portion and electrically coupled to the terminal socket;
• a second coil, disposed around the outside of the first coil, wherein the first coil and the second coil are spaced apart from each other, the second coil has a plurality of copper sheets, and the copper sheets are located between the first baffle and the second baffle;
• a locating piece, correspondingly disposed on the winding frame, used to locate the second coil;
• and
• two iron core pieces, respectively disposed on the second baffle of the winding frame and the locating piece, wherein the iron core pieces are disposed so as to pass through the through hole of the winding portion.