Position determining unit, comprising a number of N identical sensor units (Sn = 1... N), which are arranged at predetermined spacings at positions (Pn) along a path, and a transmitter, - wherein the transmitter is movable along the path and has a first end and a length extending from the first end parallel to the path and comprises a ferromagnetic material, - wherein each sensor unit (Sn) comprises a support, a first supply voltage terminal, a second voltage supply terminal, a measuring unit with a switch output and a bias magnet, - wherein the measuring unit comprises at least one magnetic field sensor (54.1, 54.2) in order to provide a sensor signal dependent on the measurement signal of the magnetic field sensor, and the measuring unit is arranged by a lower side on an upper side of the support, - wherein the bias magnet has a first pole and a second pole, - wherein the switch output is switched to an on state or an off state in dependence on the sensor signal exceeding a threshold value or falling below a threshold value, - wherein the first supply voltage terminal of each sensor (Sn) is connected with a supply voltage (Vsup), - wherein a first sensor unit is arranged at a start of the path and - wherein a last sensor unit is arranged at an end of the path, characterised in that - the second supply voltage terminal of the first sensor unit is connected with a reference potential and the first sensor unit has a current take up Isup, - the second supply voltage terminal of each further sensor (Sn>1) is connected with the switch output of the preceding sensor unit (Sn-1) and the respective further sensor unit (Sn) can be switched on or off by means of the switch output of the preceding sensor unit (Sn-1) and the respective further sensor unit (Sn) in the switched-on state has a current take up Isup, - a current measuring unit is provided and the current measuring unit is arranged in front of the first supply voltage terminal of the first sensor unit or in front of the second supply voltage terminal of the first sensor unit, - wherein the current take ups Isup of all switched-on sensor units (Sn) contribute to a sum current Isum measured by means of the current measuring unit and wherein the sum current Isum is a multiple of the current take ups Isup and is proportional to a position (Pp) of the first end of the transmitter. - wherein the transmitter is movable along the path and has a first end and a length extending from the first end parallel to the path and comprises a ferromagnetic material, - wherein each sensor unit (Sn) comprises a support, a first supply voltage terminal, a second voltage supply terminal, a measuring unit with a switch output and a bias magnet, - wherein the measuring unit comprises at least one magnetic field sensor (54.1, 54.2) in order to provide a sensor signal dependent on the measurement signal of the magnetic field sensor, and the measuring unit is arranged by a lower side on an upper side of the support, - wherein the bias magnet has a first pole and a second pole, - wherein the switch output is switched to an on state or an off state in dependence on the sensor signal exceeding a threshold value or falling below a threshold value, - wherein the first supply voltage terminal of each sensor (Sn) is connected with a supply voltage (Vsup), - wherein a first sensor unit is arranged at a start of the path and - wherein a last sensor unit is arranged at an end of the path, characterised in that - the second supply voltage terminal of the first sensor unit is connected with a reference potential and the first sensor unit has a current take up Isup, - the second supply voltage terminal of each further sensor (Sn>1) is connected with the switch output of the preceding sensor unit (Sn-1) and the respective further sensor unit (Sn) can be switched on or off by means of the switch output of the preceding sensor unit (Sn-1) and the respective further sensor unit (Sn) in the switched-on state has a current take up Isup, - a current measuring unit is provided and the current measuring unit is arranged in front of the first supply voltage terminal of the first sensor unit or in front of the second supply voltage terminal of the first sensor unit, - wherein the current take ups Isup of all switched-on sensor units (Sn) contribute to a sum current Isum measured by means of the current measuring unit and wherein the sum current Isum is a multiple of the current take ups Isup and is proportional to a position (Pp) of the first end of the transmitter.