A circuit configuration for obtaining a binary output signal, comprising: a magnetic-field sensor, which is supplied at two terminals (2; 3) with a stabilized supply voltage and which delivers from these terminals (2; 3) a current signal essentially alternating in pulse shape between two current values; a voltage-supply unit to supply the magnetic-field sensor with the stabilized supply voltage; a signal-conditioning stage for forming an analogue voltage signal from a measuring signal; an analogue/digital converter stage for obtaining a digital voltage signal from the analogue voltage signal; and a control stage for: obtaining a first and a second signal value from the digital voltage signal, wherein the signal values represent the two current values of the current signal, alternating in pulse shape, as supplied by the magnetic-field sensor; supplying the currently obtained first and second signal values to a memory device after every pulse-shaped change in the current signal, where they are stored; and identifying a digital changeover-threshold signal in accordance with a first algorithm from the stored first and second signal values; the circuit configuration further comprising: the memory device for storing the currently obtained first and second signal values; a digital/analogue converter stage for obtaining an analogue changeover-threshold signal from the digital changeover-threshold signal; and a comparator for comparing the analogue voltage signal with the analogue changeover-threshold signal and for creating the binary output signal in accordance with this comparison; the circuit configuration being characterized by comprising: a measuring device for tapping the pulse-shaped current signal from the magnetic-field sensor and for delivering the measuring signal; wherein the voltage-supply unit comprises an amplifier stage, with feedback via the measuring device, to supply the stabilized supply voltage. a magnetic-field sensor, which is supplied at two terminals (2; 3) with a stabilized supply voltage and which delivers from these terminals (2; 3) a current signal essentially alternating in pulse shape between two current values; a voltage-supply unit to supply the magnetic-field sensor with the stabilized supply voltage; a signal-conditioning stage for forming an analogue voltage signal from a measuring signal; an analogue/digital converter stage for obtaining a digital voltage signal from the analogue voltage signal; and a control stage for: obtaining a first and a second signal value from the digital voltage signal, wherein the signal values represent the two current values of the current signal, alternating in pulse shape, as supplied by the magnetic-field sensor; supplying the currently obtained first and second signal values to a memory device after every pulse-shaped change in the current signal, where they are stored; and identifying a digital changeover-threshold signal in accordance with a first algorithm from the stored first and second signal values; obtaining a first and a second signal value from the digital voltage signal, wherein the signal values represent the two current values of the current signal, alternating in pulse shape, as supplied by the magnetic-field sensor; supplying the currently obtained first and second signal values to a memory device after every pulse-shaped change in the current signal, where they are stored; and identifying a digital changeover-threshold signal in accordance with a first algorithm from the stored first and second signal values; the circuit configuration further comprising: the memory device for storing the currently obtained first and second signal values; a digital/analogue converter stage for obtaining an analogue changeover-threshold signal from the digital changeover-threshold signal; and a comparator for comparing the analogue voltage signal with the analogue changeover-threshold signal and for creating the binary output signal in accordance with this comparison; the circuit configuration being characterized by comprising: a measuring device for tapping the pulse-shaped current signal from the magnetic-field sensor and for delivering the measuring signal; wherein the voltage-supply unit comprises an amplifier stage, with feedback via the measuring device, to supply the stabilized supply voltage. the memory device for storing the currently obtained first and second signal values; a digital/analogue converter stage for obtaining an analogue changeover-threshold signal from the digital changeover-threshold signal; and a comparator for comparing the analogue voltage signal with the analogue changeover-threshold signal and for creating the binary output signal in accordance with this comparison; the circuit configuration being characterized by comprising: a measuring device for tapping the pulse-shaped current signal from the magnetic-field sensor and for delivering the measuring signal; wherein the voltage-supply unit comprises an amplifier stage, with feedback via the measuring device, to supply the stabilized supply voltage. a measuring device for tapping the pulse-shaped current signal from the magnetic-field sensor and for delivering the measuring signal; wherein the voltage-supply unit comprises an amplifier stage, with feedback via the measuring device, to supply the stabilized supply voltage.