The main advantages of toroidal transformer are lower radiation field and higher efficiency. The given capacity can be reached at half the size and weight, and the temperature of the transformer can be reduced if a transformer with a slightly larger capacity is used. The center hole fixation makes the toroidal type transformer easy to install on the printed circuit board. Toroidal transformer has a high degree of flexibility, according to the requirements of the chassis and integral assembly, design transformer size. Because the production of ring transformer does not need punching die, also does not need coil frame injection mold, so the production cycle is short, suitable for small and medium-sized batch production, can meet the needs of modern electronic equipment constantly changing. Because the ring transformer has low noise retention, many manufacturers use it for high fidelity audio equipment and video display terminals, power amplifiers, electronic test instruments and general equipment