Abstract: The invention concerns an electrical current sensor comprising a magnetic circuit (3), with an air gap (3a), a winding (4) on the magnetic circuit in which a current to be measured flows, a magnetic field detector (5) arranged in the air gap, and a support plate (2) carrying an electrical circuit (6) configured to amplify an output signal from the magnetic field detector. The support plate (2) comprises a main part (21) and a lateral extension (23), the entire unit having an area cut away from the overall rectangular shape of the plate. The turns (4a) of the winding (4) are arranged at that area in such a way that the thickness of the sensor depends on the transverse dimensions of the winding.