Abstract: A position determining device for an adjustment device including two continuous potentiometers having sliders movable to respective positions determininng respective resistance values of the potentiometers, the sliders being coupled with the adjustment drive so that the respective resistance values determined by the positions of the sliders correspond to a set position of the adjustment drive, a device for driving each of the sliders with a transmission ratio different from one another so that the potentiometers have a resistance value different from one another for a given set position of the adjustment drive, and a device for establishing a differential value from the different resistance values as a measure of the set position of the adjustment drive.