Patent ID: 7307410

Claim:
An alternating current detection coil for carrying out a non-contact detection of an alternating current, wherein the alternating current detection coil, which is a toroidal coil, comprising: plural radial-line conductors which are formed on a front face and a rear face of an insulating substrate so as to radiate out from a periphery of an opening provided on the insulating substrate; conductive connection parts and conductive first through-holes which extend in a circumferential direction to connect electrically each end of radial-line conductors on the front face and the rear face respectively on either one of an outer side or an inner side of the radial-line conductors; and conductive second through-holes which connect electrically each end of radial-line conductors on the front face and the rear face respectively on other one of the outer side and the inner side of the radial-line conductors, wherein plural winding turns are consecutively formed by a connection of each radial-line conductor on the front face and the rear face respectively through the conductive connection parts and the first and the second through-holes, the plural winding turns comprise a forward coil which winds in one direction and a backward coil which winds in a reverse direction with returning consecutively from an end of the forward coil, each winding turn of the forward coil and the backward coil is disposed alternately on both the front face and the rear face, each conductive connection part is routed to avoid a contact with a next radial-line conductor on both the front face and the rear face, and each shape of the radial-line conductors in the forward coil and the backward coil and the conductive connection parts on the front face and the rear face are identical with each other.