Hall-effect sensors are suitable for proximity rotational speed recording on gears with a small module and high resolution. The various models can handle a wide range of applications as well as the harshest of conditions. Hall-effect sensors are used in wide-ranging mechanical engineering, vehicle and mobile working machine applications, as well as in hydraulic drives. The sensor detects the movement of ferromagnetic structures such as gears via the change in the magnetic flux and is biased using a permanent magnet. Meanwhile, the teeth and gaps which traverse the sensor have varying impacts on the magnetic field, which changes the Hall voltage on a hall-effect sensor. These changes to the magnetic field can then be converted to electrical values, filtered and processed. The sensor output signal is a square-wave voltage which reflects the change in the magnetic field.