Hall sensor is a kind of magnetic field sensor based on Hall effect. Hall effect is a kind of magnetoelectric effect. Semiconductors and conductive fluids also have this effect, and the Hall effect of semiconductors is much stronger than that of metals. Various Hall elements made from this phenomenon are widely used in industrial automation technology, detection technology and information processing. Hall effect is a basic method to study the properties of semiconductor materials. The Hall coefficient measured by Hall effect experiment can be used to judge the important parameters of semiconductor materials, such as conductivity type, carrier concentration and carrier mobility.