Abstract: A common mode filter for reducing differential mode signal converting to common mode signal comprising: a core-cylinder, a first coil, and a second coil; wherein two ends of the core-cylinder respectively extend and set with a first flange and a second flange; wherein m1, m2, and m3 turns and n1, n2, and n3 turns are respectively and sequentially wound and set on the first winding portion, the second winding portion, and the third winding portion of the first winding area, the second winding area, and the third winding area of the first coil and the second coil. Therefore, the present invention can effectively reduce the mode conversion characteristic (Scd), and can also improve the noise reduction performance of the product; thereby greatly upgrading the practicality of the present invention; and the present invention has a simple process, therefore the product yield can be further upgraded to achieve the effect.

Abstract: A pulse transformer includes a drum core having a winding core, two flanges on end portions of the winding core and each having a notch formed in the upper portion, two terminal electrodes and a center tap disposed on one of the flanges, two further terminal electrodes and another center tap disposed on the other flange, a coil includes four wires wound around the winding core of the drum core and connected to the terminal electrodes and the center taps, two of the wires are wound in one direction, and the other wires are wound in another direction, two of the wires cross each other at the inner surface of one of the flanges, and the other wires cross each other at the inner surface of the other flange.

Abstract: A coil filter includes a core member having two end members extended from two end portions, the left end member includes a front protrusion, a rear protrusion, and a middle protrusion extended upwardly beyond the core member, the front protrusion includes a width (W) greater than that of the rear protrusion and the middle protrusion, the second end member includes a rear projection, a front projection, and a middle projection extended upwardly beyond the core member, the rear projection includes a width (T) greater than the width (t) of the front projection and the middle projection, and a coil member wound onto the core member and disposed between the end members without wasting the spaces of the core member.