Such a servomechanism is usable for controlling various mechanizations, such as gear extension or rotation of any element via a supplemental reducer. I used such sensors for leveling-off the video camera in respect of the position of the mechanical gyroscope. A Hall sensor ensures a proportional response to a change of the magnetic field, taking into account the polarity. An absence of magnetic field or the neutral magnetic field (in case of equal distances from the opposite poles) in the transformed servomechanism conforms to the neutral position of the potentiometer in an ordinary servomechanism. The sensor responds to a shift or rotation of the magnet; it is also possible to use two magnets in two extreme positions.