Abstract: Open-loop electrical current sensor (1) for measuring the electrical current flowing in a primary conductor, comprising a magnetic circuit (3) with an air-gap (4), and a magnetic field sensing device (5) positioned at least partially in said air-gap. The magnetic field sensing device comprises a circuit board (7), a first magnetic field detector (8) mounted on the circuit board, and a second magnetic field detector (11). The second magnetic field detector comprises a conductive coil formed on the circuit board, the output signals of the first magnetic field detector and the second magnetic field detector being adapted for connection to a signal processing circuit (6) generating an output signal representative of the primary electrical current.

Abstract: An open-loop current sensor comprising a magnetic circuit having an air gap, a magnetic field detector disposed in the air gap, and a primary conductor having one or more turns surrounding the magnetic circuit, the current to be measured flowing in the primary conductor, the sensor being characterised in that the turns of the primary conductor are disposed close to the air gap, on each side of the air gap.

Abstract: A sensor of the type comprising a magnetic circuit coupled to the lead, wherein circulates the current to be measured and presenting an airgap wherein is arranged a Hall cell (3) and coupled to a compensation coil (5) supplied, as well as the Hall cell, by a unipolar current source (V.sub.+, earth), comprises a four-branch bridge supply circuit wherein the coil (5) is connected to form a diagonal. The current source and a measurement resistor (R) are mounted in series with said bridge circuit. The variable conduction elements (8, 9, 15, 16) are mounted in the four branches of the bridge and are so controlled as to cause a make-up current to circulate in the coil (5), in one direction or the other, as a function of the residual flow direction indicated by the Hall cell (3), through two respective opposite branches of the bridge circuit. The other two opposite branches being non-conductive.