Patent ID: 8525632

Claim:
A reactor comprising a coil and a magnetic core, the coil being formed by winding a wire, the magnetic core including an internal core portion that is inserted through the coil and a couple core portion that covers at least a part of an outer periphery of the coil, the core portions forming a closed magnetic path, wherein 1<(B 1 /B 2 ) and 0.17×(B 1 /B 2 )+0.42≦(S 1 ×B 1 )/(S 2 ×B 2 )≦0.50×(B 1 /B 2 )+0.62 are satisfied, where S 1 is a cross-sectional area of the internal core portion, B 1 is a saturation magnetic flux density of the internal core portion, S 2 is a cross-sectional area of the couple core portion, B 2 is a saturation magnetic flux density of the couple core portion, (B 1 /B 2 ) is a saturation magnetic flux density ratio between the core portions, and (S 1 ×B 1 )/(S 2 ×B 2 ) is a magnetic flux ratio between the core portions.