Among various methods of non-contact current measurement, current measurement based on the Hall principle is the most commonly used method. When the magnetic field is concentrated, the Hall element can sense the magnetic field and generate a voltage, which is called the Hall voltage and can be used for direct output or feedback control. From this structure, it can be seen that when the cable of the measured current is close to the Hall element, a relatively obvious magnetic field change will occur, resulting in the generation of position errors. In order to reduce this error, the method of symmetrical arrangement of multiple Halls and multiple breaths can usually be used to solve the problem, but no matter what method is adopted, the position error cannot be fundamentally eliminated, because the number of Hall elements cannot be increased indefinitely. This is why the user manual of the Hall sensor usually requires the user to center the measured current row (cable) on the perforated part as much as possible when measuring the current. Sometimes in order to eliminate the influence of position error, a built-in current bank can be used.