Abstract: A transformer for reducing the electromagnetic interference (EMI) effect is disclosed. The transformer includes a bobbin; a magnetic core assembly partially sleeved by the bobbin; a first primary winding coiled around the bobbin; a secondary winding coiled on the first primary winding; and a first shielded element disposed between the first primary winding and the secondary winding for disconnecting the EMI transmission from the first primary winding to the secondary winding. The first primary winding includes a first winding portion and a second winding portion, and the first winding portion has larger EMI comparing to the second winding portion. The first winding portion of the first primary winding is adjacently disposed to the magnetic core assembly for shielding the EMI of the first primary winding by using the magnetic core assembly.

Abstract: A transformer for reducing the electromagnetic interference (EMI) effect is disclosed. The transformer includes a bobbin; a magnetic core assembly partially sleeved by the bobbin; a first primary winding coiled around the bobbin; a secondary winding coiled on the first primary winding; and a first shielded element disposed between the first primary winding and the secondary winding for disconnecting the EMI transmission from the first primary winding to the secondary winding. The first primary winding includes a first winding portion and a second winding portion, and the first winding portion has larger EMI comparing to the second winding portion. The first winding portion of the first primary winding is adjacently disposed to the magnetic core assembly for shielding the EMI of the first primary winding by using the magnetic core assembly.

Abstract: A method for eliminating noise interference and acoustic noise by a printed circuit board ground plane layout is disclosed. The method is applied to a circuit system having multiple outputs, wherein the circuit system has a first power converting module, a second power converting module and a printed circuit board. The first power converting module and the second power converting module respectively includes a first ground pin group and a second ground pin group. The method includes the steps of (a) connecting each ground pin of the first ground pin group to a respective solder point and connecting each solder point to a first node, and connecting each ground pin of the second ground pin group to a respective solder point and connecting each solder point to a second node, and (b) connecting the first node and the second node to a common node and connecting the common node to a solder point of a common ground terminal on the printed circuit board ground plane.

Abstract: A method for eliminating noise interference and acoustic noise by a printed circuit board ground plane layout is disclosed. The method is applied to a circuit system having multiple outputs, wherein the circuit system has a first power converting module, a second power converting module and a printed circuit board. The first power converting module and the second power converting module respectively includes a first ground pin group and a second ground pin group. The method includes the steps of (a) connecting each ground pin of the first ground pin group to a respective solder point and connecting each solder point to a first node, and connecting each ground pin of the second ground pin group to a respective solder point and connecting each solder point to a second node, and (b) connecting the first node and the second node to a common node and connecting the common node to a solder point of a common ground terminal on the printed circuit board ground plane.