For the wound rotary transformer, the alternating magnetic field generated by the field winding is periodically stable, and the cutting magnetic field area of the metal conductor of the secondary winding changes, which causes the magnetic flux to change, and then the induced electromotive force changes to form a voltage signal, which is converted by A/D Digital signal (ie angle signal);

The principle of reluctance resolver is different. Similarly, when the AC magnetic field generated by the excitation winding is periodically stable, the rotor rotation causes the air gap magnetic field between the stator and the rotor to change, and the feedback to the secondary winding inductance changes, thereby inducing electromotive force It changes to form a voltage signal, which is converted into a digital signal (that is, an angle signal) through A/D.