A coil wire includes a core wire and a winding wire. The winding wire is wound around a circumference of the core wire so as to form a plurality of spirals. The coil wire satisfies one of: (i) an outer surface of the core wire is exposed, and a distance between the outer surface of the core wire and an inner circumferential surface of part of the winding wire is smaller than a thickness of a first insulating film coated on the winding wire; or (ii) the outer surface of the core wire is coated by a second insulating film, and a distance between an outer surface of the second insulating film and the inner circumferential surface of part of the winding wire is smaller than a thickness of a thicker one of the first insulating film and the second insulating film.

A coil component includes: a body having a first surface and a second surface opposing each other, and a first end surface and a second end surface connecting the first surface and the second surface to each other and opposing each other in a first direction; a coil unit disposed in the body; and first and second external electrodes disposed on the body, and respectively connected to the coil unit, wherein the coil component includes a slit portion formed in at least one of the first surface of the body and the second surface of the body, spaced apart from each of the first and second external electrodes, and extending in a direction intersecting the first direction, and a dimension W.sub.s of the slit portion in the first direction is less than or equal to 20.8% of a dimension L.sub.c of the coil component in the first direction.

A coil component includes: a body having a first surface and a second surface opposing each other, and a first end surface and a second end surface connecting the first surface and the second surface to each other and opposing each other in a first direction; a coil unit disposed in the body; and first and second external electrodes disposed on the body, and respectively connected to the coil unit, wherein the coil component includes a slit portion formed in at least one of the first surface of the body and the second surface of the body, spaced apart from each of the first and second external electrodes, and extending in a direction intersecting the first direction, and a dimension W.sub.s of the slit portion in the first direction is less than or equal to 20.8% of a dimension L.sub.c of the coil component in the first direction.

A inductive component is provided, which comprises a magnetic core, an insulation body formed of an electrically insulating material and having the magnetic core accommodated therein, and a coil body having at least one winding wound thereon. The insulation body comprises at least two mechanically connected insulation wall sections, which each face, at least partially, a respective side surface section of the magnetic core. The coil body comprises at least one contact element attached to a side surface section of the coil body and used for establishing an electric connection to the at least one winding, and a magnetic core accommodation in which the magnetic core accommodated in the insulation body is partially accommodated. A side surface section of the magnetic core, which faces the contact element, is covered, at least partially, by an insulation wall section of the insulation body.

An insulating element includes a first coil; a second coil; and an inter-layer insulating film located between the first coil and the second coil. The inter-layer insulating film includes a first layer, a second layer, and a third layer located between the first layer and the second layer. The first layer is located between the first coil and the third layer. The second layer is located between the second coil and the third layer. A bandgap of the third layer is narrower than a bandgap of the first layer and a bandgap of the second layer.

The invention comprises an apparatus, comprising: an inductor, the inductor comprising: an electrical turn about an inductor core, the inductor core comprising a ring shape; the electrical turn comprising a first width at a first radial distance from a center of the inductor core and a second width at a second radial distance from the center, the second width at least ten percent larger than the first width. Optionally and preferably, the electrical turn comprises: a first cast element and a second cast element and a mechanical connection connecting the first cast element to the second cast element, such as an aluminum weld.

An inductor component includes a main body formed in a flat-plate shape and including a magnetic layer; an inductor wiring line disposed on a plane inside the main body; a first vertical wiring line that extends, from a pad portion which is an end portion of the inductor wiring line, in a first direction to pass through the inside of the main body, and is exposed on a first principal surface side of the main body; a second vertical wiring line that extends, from the pad portion of the inductor wiring line, in a second direction to pass through the inside of the main body, and is exposed on a second principal surface side of the main body; and an insulation layer of a non-magnetic body. The first vertical wiring line includes a via conductor and a columnar wiring line. The second vertical wiring line includes a columnar wiring line.

An inductor component includes a main body formed in a flat-plate shape and including a magnetic layer; an inductor wiring line disposed on a plane inside the main body; a first vertical wiring line that extends, from a pad portion which is an end portion of the inductor wiring line, in a first direction to pass through the inside of the main body, and is exposed on a first principal surface side of the main body; a second vertical wiring line that extends, from the pad portion of the inductor wiring line, in a second direction to pass through the inside of the main body, and is exposed on a second principal surface side of the main body; and an insulation layer of a non-magnetic body. The first vertical wiring line includes a via conductor and a columnar wiring line. The second vertical wiring line includes a columnar wiring line.

A reactor includes a coil, a magnetic core having an inner core portion inside a winding portion, and an inner interposed member insulating the winding portion from the inner core portion. The inner interposed member includes a thin portion with a small thickness formed by a recess, and a thick portion with a thickness larger than that of the thin portion. The inner core portion includes a core-side projecting portion with a shape conforming to a shape of the inner peripheral face of the thin portion. The thickness of the thin portion is 0.2 mm or more and 1.0 mm or less, and the thickness of the thick portion is 1.1 mm or more and 2.5 mm or less. Clearances are in part of a portion between the inner core portion and the inner interposed member and of a portion between the inner interposed member and the winding portion.

A reactor includes a coil, a magnetic core having an inner core portion arranged inside a winding portion, and an inner interposed member insulating the winding portion from the inner core portion. The inner interposed member includes a thin portion with a small thickness, and a thick portion with a thickness larger than that of the thin portion. The inner core portion includes, on an outer peripheral face facing the inner interposed member, a core-side projecting portion with a shape conforming to a shape of the inner peripheral face of the thin portion. The thickness of the thin portion is 0.2 mm or more and 1.0 mm or less, and the thickness of the thick portion is 1.1 mm or more and 2.5 mm or less. There is a clearance in at least part of a portion between the inner interposed member and the winding portion.