A Hall Effect Sensor or a Hall Effect Device is a transducer which varies its output voltage in response to changes in magnetic field.
Unlike reed contacts, Hall Effect Devices require amplification circuits and an external power source for operation.
A Hall effect sensor (also known as a Hall sensor or Hall probe) is any sensor incorporating one or more Hall elements, each of which produces a voltage proportional to one axial component of the magnetic field vector B using the Hall effect (named for physicist Edwin Hall).
Hall sensors are used for proximity sensing, positioning, speed detection, and current sensing applications and are common in industrial and consumer applications. Hundreds of millions of Hall sensor integrated circuits (ICs) are sold each year by about 50 manufacturers, with the global market being valued at around a billion dollars.
