Working principle of Hall effect sensor

- Mar 25, 2020-

Hall voltage changes with the change of magnetic field strength. The stronger the magnetic field is, the higher the voltage is, the weaker the magnetic field is, and the lower the voltage is. Hall voltage is very small, usually only a few millivolts, but by amplifying the amplifier in the integrated circuit, the voltage can be amplified enough to output a strong signal. If Hall integrated circuit is used as a sensor, it is necessary to change the magnetic field intensity mechanically. The method shown in the figure below is to use a rotating impeller as the switch to control the magnetic flux. When the impeller blade is in the air gap between the magnet and the hall integrated circuit, the magnetic field deviates from the integrated circuit and the Hall voltage disappears. In this way, the change of output voltage of Hall integrated circuit can indicate a certain position of impeller drive shaft. Using this working principle, the hall integrated circuit chip can be used as ignition timing sensor. Hall effect sensor belongs to passive sensor. It needs external power supply to work. This feature enables it to detect the low speed operation.