Precise current sensor by means of small-angle magnetization rotation using amorphous wire and its industrial application

The precise current sensor described consists of a detecting element of the magnetic field produced by the measuring current, a compensator, and a feedback coil. The alternating excitation current flows with a frequency of 250 kHz through the amorphous wire that is a part of the detecting element. The excitation current causes a rotating field in the amorphous wire in the circular direction. The second harmonic voltage e_2f occurs in the sense coil wound around the wire. The measuring current, which is at right angles to the wire, affects the rotating field, so that the e_2f induced in the sense coil varies. The compensator consists of high-gain operational amplifiers. The sensor´s components are described in detail, and the results of tests on the sensor are presented