Choke

A choke comprising:

• a single-piece core having a first board, a second board, and a pillar located between the first and second boards, a winding space being located among the first board, the second board and the pillar, a permeability of the core being in a first range of 25 to 60;
• a wire wound around the pillar and located in the winding space;
• and
• a magnetic material filled in the winding space and encapsulating the wire, a permeability of the magnetic material being in a second range of 4 to 21, wherein the permeability of the core and the permeability of the magnetic material are paired to increase a saturation current of the choke, wherein when a maximum current at 1.5 A is inputted to the choke, the saturation current of the choke is at least 80 percent of the maximum current at 1.5 A.

A choke comprising:

• a core structure having a first board, a second board, and a pillar located between the first and second boards, a winding space being located among the first board, the second board and the pillar, wherein the pillar has a non-circular and non-rectangular cross section along a direction substantially perpendicular to an axial direction of the pillar, wherein a circumference of the cross section of the pillar includes a first substantially straight edge, a first arc edge, a second substantially straight edge, and a second arc edge on four sides of the circumference, respectively, wherein the substantially straight edges are interleaved with the arc edges on the circumference of the cross section of the pillar, and wherein each arc edge is convex with respect to said substantially straight edges, wherein the cross section of the pillar has a first axis and a second axis intersecting with each other at a center of the cross section along the first axis is longer than or substantially equal to a length of the cross section along the second axis, wherein the second substantially straight edge is shorter than the length of the cross section along the second axis, and an inequality is satisfied:
• 0<d<½Y;
• wherein Y represents the length of the cross section along the second axis, and d represents a difference of ½ Y and ½ of a length of the second substantially straight edge.