By applying the principle that magnetic poles with the same name repel each other and magnetic poles with different names attract each other, the rise and fall of the seesaw are realized. Its magnetic field consists of permanent magnets and electromagnets. The permanent magnet produces a fixed magnetic field, while the electromagnet produces an alternating magnetic field that varies with the direction of current. The simplest magnet model is unipolar magnetic model, which has one less magnetic pole than ordinary magnets, so it is simpler than ordinary magnets.