| 摘要 |
PROBLEM TO BE SOLVED: To provide a current sensing coil which is less susceptible to influence of external magnetic fields, allows for increasing the number of windings of toroidal coils using a circuit board of a conventional size, and has a reduced number of through-holes, which improves yield.SOLUTION: A current sensing coil has a circuit substrate having an opening and comprising a plurality of conductive layers and a plurality of insulating layers alternately laminated, and toroidal coils formed surrounding the opening, the toroidal coils being a forward wound coil and a reverse wound coil, which are wound in opposite directions with respect to a magnetic field parallel to a lamination direction of the circuit board. Through-holes 61, 81 are formed alternately along two circles having large and small diameters at respective predetermined intervals. Pairs of portions 11a and 31a, 11b and 21b, 21a and 41a, 31b and 41b of conductive patterns formed on the plurality of conductive layers to form the forward wound coil and reverse wound coil overlap with each other when viewed in the lamination direction of the circuit board. |
