Disclosed herein is a coil component that includes: a first magnetic core extending in the first direction and around which the wires are wound; a second magnetic core covering the first magnetic core from one side in a third direction; first and second terminal electrodes connected respectively to one ends of the first and second wires; and third and fourth terminal electrodes connected respectively to other ends of the first and second wires. The first and second electrodes are arranged in the first direction along the first surface of the first magnetic core, and the third and fourth terminal electrodes are arranged in the first direction along the second surface of the first magnetic core.

A drum core includes a core portion that extends in an axial direction, first and second flange portions respectively disposed at first and second ends of the core portion in the axial direction, and first and second terminal electrodes respectively disposed at the first and second flange portions. The first flange portion includes a bottom surface that is substantially parallel to the axial direction and on which the first terminal electrode is disposed, an outer end surface that is substantially perpendicular to the axial direction and that faces outward away from the core portion, and a first ridge portion and a second ridge portion respectively disposed at a first end and a second end of the outer end surface in a width direction substantially parallel to the bottom surface and the outer end surface, and the first ridge portion and the second ridge portion have different shapes.

A common mode choke coil includes a core, and first and second coils opposed to each other and wound on the core. The core can have a square shape, or an elongated shape having a long axis and a short axis when viewed in a direction along a central axis of the core. Each of the first and second coils is a single-layer coil. An area of a cross-section of the core taken perpendicular to a circumferential direction of the core is constant in the circumferential direction of the core. The cross-section of the core has a quadrilateral shape.

A differential mode choke coil component includes a substantially drum-shaped core, a substantially plate-shaped core, and first and second wires. The plate-shaped core is secured to each of the first and second flanges by using an adhesive with the first major surface facing the top surface of each of the first and second flanges with a spacing. The spacing has a mean value greater than or equal to about 20 μm between the first major surface and the top surface of each of the first and second flanges.

A common mode choke is provided, including a hollow ferrite core, a plurality of coils wound around the ferrite core, and a substrate. Each of the coils has a first end and a second end. The substrate is disposed on the side of the ferrite core and has a plurality of through holes. The first and second ends of the coils are engaged in the through holes. When viewed along the central axis of the ferrite core, the first and second ends of the coils are located on the outer side the ferrite core.

A direct-current superimposing circuit includes differential signal lines, capacitors, a common mode choke coil, a winding-type coil component, and a DC power supply which are disposed at a circuit board. The winding-type coil component includes a core, two pairs of terminal electrodes, and two windings (a first winding and a second winding). On the end surface of a flange portion, the terminal electrodes in one of the two pairs and the terminal electrodes in the other one of the two pairs are placed to face each other across the winding center of a winding core. The winding start and winding end of the first winding are connected to the terminal electrodes in one of the two pairs. The winding start and winding end of the second winding are connected to the terminal electrodes in the other one of the two pairs.

An electronic circuit includes a shield line including first and second signal lines and a shield. The first and second signal lines are connected to a signal source, and the shield coating is around the first and second signal lines. The electronic circuit further includes a signal ground near the signal source; a frame ground that is isolated from the signal ground and connected to the shield; a common mode choke coil that includes first, second and third coils magnetically coupled to one another; and a capacitor that is connected in parallel with the third coil. The first coil is connected in series between the signal source and the first signal line. The second coil is connected in series between the signal source and the second signal line. The third coil and the capacitor that are connected in parallel are connected between the signal ground and the frame ground.

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 m.sub.1, m.sub.2, and m.sub.3 turns and n.sub.1, n.sub.2, and n.sub.3 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.

A coil component includes a core including a winding core portion, a first flange portion, and a second flange portion, and a first wire and a second wire that are wound around the winding core portion in the same direction and that form a winding portion. The winding portion includes a second intersecting portion along a third side surface of the winding core portion at a position on the winding portion nearest to the second flange portion.

A coil component comprising a core including a winding core having a shape extending in a constant direction, a first flange disposed at a first end in an extending direction of the winding core, and a second flange disposed at a second end in the extending direction of the winding core; first and second electrodes disposed on the first flange; third and fourth electrodes disposed on the second flange; and a coil including a first wire wound around the winding core and electrically connected to the first and third electrodes, and a second wire electrically connected to the second and fourth electrodes. The first and second flanges each have an inner surface facing the winding core, an outer surface facing toward the side opposite to the inner surface, a lower surface connecting the inner and outer surfaces, and an upper surface facing the side opposite to the lower surface.