Abstract: An excitation core includes an annular strip-shaped magnetic substance, in which both ends of the strip-shaped magnetic substance are overlapped in a thickness direction and are in contact with one another. A sensor head includes: this excitation core and a magnetism collecting body. The magnetism collecting body includes a strip-shaped first magnetism collector and a strip-shaped second magnetism collector, the first magnetism collector having both ends thereof in contact with both ends of the second magnetism collector to form the annular magnetism collecting body, the magnetism collecting body being disposed on an inside or an outside of the reinforcing body.

Abstract: An excitation core includes a first strip-shaped magnetic substance and a second strip-shaped magnetic substance. The first strip-shaped magnetic substance has both ends mutually overlapped with and mutually in contact with both ends of the second strip-shaped magnetic substance in a thickness direction. A sensor head includes this excitation core and a magnetism collecting body. This magnetism collecting body includes strip-shaped first magnetism collector and second magnetism collector. Both ends of the first magnetism collector and both ends of the second magnetism collector are in contact with one another to form the annular magnetism collecting body. This magnetism collecting body is disposed at an inside or an outside of the reinforcing body.

Abstract: An excitation core includes an annular strip-shaped magnetic substance, in which both ends of the strip-shaped magnetic substance are overlapped in a thickness direction and are in contact with one another. A sensor head includes: this excitation core and a magnetism collecting body. The magnetism collecting body includes a strip-shaped first magnetism collector and a strip-shaped second magnetism collector, the first magnetism collector having both ends thereof in contact with both ends of the second magnetism collector to form the annular magnetism collecting body, the magnetism collecting body being disposed on an inside or an outside of the reinforcing body.

Abstract: An excitation core includes a first strip-shaped magnetic substance and a second strip-shaped magnetic substance. The first strip-shaped magnetic substance has both ends mutually overlapped with and mutually in contact with both ends of the second strip-shaped magnetic substance in a thickness direction. A sensor head includes this excitation core and a magnetism collecting body. This magnetism collecting body includes strip-shaped first magnetism collector and second magnetism collector. Both ends of the first magnetism collector and both ends of the second magnetism collector are in contact with one another to form the annular magnetism collecting body. This magnetism collecting body is disposed at an inside or an outside of the reinforcing body.

Abstract: An indirect feedback type flyback converter that compares favorably with the direct feedback type flyback converter in controllability of secondary output voltage, wherein the converter is arranged so that a switching signal, which is induced in a secondary winding when a direct current input voltage, applied to a primary winding, is turned ON and OFF by a switching element, is smoothed by rectification and fed to a load and that an output voltage is detected using a switching signal induced in an auxiliary winding to transmit a control signal to the switching element for the purpose of stabilizing the output voltage; wherein the primary, secondary and auxiliary windings are formed on respective coil formation surfaces of a coil laminate as convoluted shaped conductor patterns disposed between a core hole at the center of the pattern and the border of the coil formation surface, with the auxiliary winding being disposed to be near the border of the coil formation surface.