Topic 33. Magnetic Field Sensors
A Hall effect sensor responds to the intensity of the magnetic field around it. It has three terminals. If there is no magnet close to it, its output voltage is about half the supply voltage.
If the South pole of a magnet is brought close to it, the output voltage rises. The amount of rise is in proportion to the strength of the field. If the North pole of a magnet is brought close to it, the output falls.