The invention relates to a magnetic circuit (2) for carrying at least one coil (3), the circuit (2) comprising: at least one inner leg (6) and at least two outer legs (4), and a connecting part (7) for guiding the magnetic flux of the inner leg (6) towards each outer leg (4), none of the outer legs (4) having a gap width and the inner leg (6) being at least partially formed from at least one material having a relative magnetic permeability lower than that of the material(s) forming the outer legs.