MUTUAL INDUCTANCE HIGHLY INDEPENDENT OF PRIMARY WINDING POSITION AND AMBIENT FIELDS

A new design of a high precision mutual inductor is described, Its mai n features are: immunity to ambient magnetic and electric fields and i ndependence of mutual inductance on the shape and position of the prim ary winding. These results are achieved by using an electric screen an d a hollow toroidal magnetic shield, To avoid the saturation of the ma gnetic shield two windings of the same number of turns, connected in s eries-opposition, are wound, one outside and one inside the magnetic s hield.