Process for forming an electrical current sensor

The detector uses the magnetic field caused by the current, and detects this within a structure protected against external magnetic field effects. The electric current sensor operates by the detection of the magnetic field created by the current, and includes a conductive part (6) of rectangular cross-section. This has two terminals to connected the conductive element in series with the circuit carrying the current to measure. The conducting part is surrounded on three of its lateral faces by a magnetic circuit (7,7',7) having flat surfaces situated in the plane of the fourth surface of the conductor. The magnetic field detector (3) is positioned facing this fourth surface. The conductive part (6) is formed by photolithography and etching within a layer of conductive material applied to a first surface of a flat support element (1), with intermediate layers (8,9). The magnetic circuit (7) is formed by further photolithography and etching within a magnetic layer.