Magnetic sensor is widely used in the national economy, national defense construction, science and technology, health and other fields have played an important role in the modern sensor industry has become a major branch. They play an increasingly important role Sensor in all aspects such as traditional industry application and transformation, resource exploration and comprehensive utilization, environmental protection, bioengineering, traffic intelligent control and so on.
And when the magnetic moments of the adjacent magnetic layers are antiparallel, the conduction electrons of the two spin states pass through a magnetic layer with the same magnetic moment as the magnetic direction, and the other magnetic moment is opposite to the direction of its spin Of the magnetic layer, and where there is a strong scattering effect, no kind of spin state of the electrons Fuel Rail Pressure Sensor can pass through the FM / NM interface, the device presents a high resistance state. Hall switch device without contact, no wear, clear output waveform, no jitter, no rebound, high repeatability, wide operating temperature range, up to -55 ℃ ~ 150 ℃. Switch-type Hall sensor after a change in the intensity of the magnetic field, then complete a switch action, the output digital signal, you can calculate the speed of the car or machine, ABS system speed sensor, car speed and odometer, locomotive automatic door switch , Brushless DC motor, car ignition system, access control and burglar alarm, vending machines, printers and so on.
Hall sensor is the use of Hall effect generated by the potential difference to calculate the size and polarity of the external magnetic field. The magnetometer is a planar device using a CMOS process. Process relative to the general IC is more simple, generally used P-type substrate on the N-well to form a sensor, through the metal electrode to connect the sensor and other circuits. Can only perceive the magnetic field changes perpendicular to the surface of the die, thus increasing the magnetic flux concentrator, the process is to do the original die to add a layer of permalloy, can detect parallel Speed Sensor to the direction of the magnetic field. Thus, the Hall sensor to achieve from the single-axis to three-axis magnetometer by leaps and bounds.
When the external magnetic field and magnet built-in magnetic field direction into zero angle, the resistance will not change with the external magnetic field changes; but when the external magnetic field and the magnetic field of the built-in magnetic field has a certain angle, the magnet magnetization within the magnetization The resistance of the thin film alloy is changed by the change of the angle, the resistance and the magnetic field characteristic are non-linear, and each resistance is not the same as the only one. Plus the magnetic field value in correspondence. From the above figure, we can see that when the current direction and the direction of magnetization parallel, the sensor is most sensitive in the direction of current and magnetization direction of 45 degrees, the general reluctance in the vicinity of the linear area, Of the linear characteristics. GMR magnetoresistive sensor consists of four giant magnetoresistance Wheatstone bridge structure, which can reduce the external environment on the sensor output stability, increase Throttle Position Sensor the sensitivity of the sensor. When the magnetic moments of adjacent magnetic layers are distributed in parallel, the two FM / NM interfaces exhibit different resistance states, one interface is high impedance state, one interface is low resistance state, spin conduction electrons can move freely within the crystal, The device exhibits a low resistance state;