Abstract: A four-terminal network, especially for filtering frequency bands or values, behaves as an ideal winding, therefore ensures high selectivity and, if equipped with an iron core, the possibility of carrying out switch operations. The network includes a pair of closely adjacent inductor coils having parallel turns for current in opposite directions, and equal inductance with a capacitor connected to at least one end of one of the coils.

Abstract: A magnetomechanical converter for the variable adjustment of an outer circuit with great accuracy. The converter comprises an armature, a unit containing magnets for generating a magnetic field of variable intensity, and a device for varying the intensity of the generated magnetic field, wherein the armature and the generating unit are movable relatively to one another.