When ferromagnetic materials such as iron, nickel, or cobalt are subjected to an external magnetic field, the magnetic domains inside the material align, resulting in internal stress and causing changes in the shape or size of the material. This phenomenon is called magnetostriction, and the famous magneto resistive sensor has been made using this principle. Magnetic resistance sensors are based on the magnetic resistance effect. The magnetoresistance effect is the change in resistance of current carrying ferromagnetic materials under the action of a magnetic field. Magnetic resistance sensors can also be referred to as magnetically controllable resistors.And the output signal requires some signal processing to be converted into the required parameters. Obviously, the distribution of magnetic fields depends on the distance and the form of the objects (such as magnets, currents, etc.) or events that generate or interfere. Therefore, sensors and object creation should always be considered in application design. Although magnetic sensors are a bit difficult to use, they can indeed provide accurate and reliable data without physical contact. Therefore, our magneto resistive sensors are based on open-loop detection principles and have inherent isolation advantages. Therefore, when applied to current detection, the isolation effect is very good, which is also an important reason why many manufacturers use magneto resistive chips to detect current.

When current passes through ferromagnetic materials, the internal magnetization vector (M) of the ferromagnetic material is parallel to the current flow. As shown in the figure, when an external magnetic field is applied in the opposite direction of the current, the internal magnetic field vector will change its position (M1) according to the magnetic field strength. The resistance depends on the angle formed by the internal magnetization vector (M) of the ferromagnetic material and the direction of the current (I). If the current is parallel to the internal magnetization vector, the resistance is maximum. When the current forms a 90 ° angle with the internal magnetization vector, the resistance of ferromagnetic materials is minimized.

Therefore, when using a magneto resistive sensor to detect current, it is important to avoid environments with strong external magnetic fields as much as possible in order to obtain accurate output values for current detection and make your system more reliable.