Abstract: A transformer includes a drum core and a coil set wound on the drum core. The coil set includes a conductive member and an insulating layer wrapping around the conductive member. A diameter of the conductive member is between 0.07 mm and 0.2 mm, and a ratio of an outer diameter of the insulating layer to the diameter of the conductive member is between 1.35 and 2.5.

Abstract: A wireless charging coil with a high Q factor includes a plurality of wire groups. Each of the wire groups includes a plurality of wires, a self-bonding film and a plurality of insulation layers. The wires are spun together in a helical manner to form a self-woven structure of the wire group. The self-bonding film surrounds the plurality of wires, and each of the insulation layers covers a surface of a wire. The plurality of wire groups together are wound into a plurality of turns on a same winding surface, and all of the plurality of wire groups are wound on the same winding surface. Each turn is wound by the plurality of wire groups.

Abstract: A wireless charging coil with a high Q factor includes a plurality of wire groups. Each of the wire groups includes a plurality of wires, a self-bonding film and a plurality of insulation layers. The wires are spun together in a helical manner to form a self-woven structure of the wire group. The self-bonding film surrounds the plurality of wires, and each of the insulation layers covers a surface of a wire. The plurality of wire groups together are wound into a plurality of turns on a same winding surface, and all of the plurality of wire groups are wound on the same winding surface. Each turn is wound by the plurality of wire groups.