Circuit for switching on and off at least one semiconductor light source arranged within a series circuit of first light-emitting diodes (D0, D6), comprising a working constant current source a ground terminal, a field effect transistor, the at least one semiconductor light source, the series circuit of first light-emitting diodes (D0, D6), a capacitor a diode (Ddischarge), a resistor, a control current source a further resistor a further capacitor a third capacitor, a first end of the series circuit being connected to the working constant current source and a second end of the series circuit being connected to the ground terminal, and the field effect transistor being electrically connected in parallel to the at least one semiconductor light source, a source terminal (Source1) of the field effect transistor being connected to a first terminal of the at least one semiconductor light source, a drain terminal (Drain1) of the field effect transistor being connected to a second terminal of the at least one semiconductor light source, the drain terminal (Drain1) of the field effect transistor being connected via the capacitor to a gate terminal (Gate1) of the field effect transistor, the diode (Ddischarge) and the resistor being connected in parallel in a parallel circuit, and the control current source being connected via the parallel circuit to the gate terminal (Gate1) of the field effect transistor and via the further resistor to the source terminal (Source1) of the field effect transistor, the at least one semiconductor light source comprising an interconnection of a plurality of second light-emitting diodes (D1, D2, D3, D4) connected in series, characterized in that the gate terminal (Gate1) of the field effect transistor is connected to the source terminal (Source1) of the field effect transistor via the further capacitor, the third capacitor being connected in parallel to the working constant current source. a working constant current source a ground terminal, a field effect transistor, the at least one semiconductor light source, the series circuit of first light-emitting diodes (D0, D6), a capacitor a diode (Ddischarge), a resistor, a control current source a further resistor a further capacitor a third capacitor, a first end of the series circuit being connected to the working constant current source and a second end of the series circuit being connected to the ground terminal, and the field effect transistor being electrically connected in parallel to the at least one semiconductor light source, a source terminal (Source1) of the field effect transistor being connected to a first terminal of the at least one semiconductor light source, a drain terminal (Drain1) of the field effect transistor being connected to a second terminal of the at least one semiconductor light source, the drain terminal (Drain1) of the field effect transistor being connected via the capacitor to a gate terminal (Gate1) of the field effect transistor, the diode (Ddischarge) and the resistor being connected in parallel in a parallel circuit, and the control current source being connected via the parallel circuit to the gate terminal (Gate1) of the field effect transistor and via the further resistor to the source terminal (Source1) of the field effect transistor, the at least one semiconductor light source comprising an interconnection of a plurality of second light-emitting diodes (D1, D2, D3, D4) connected in series, characterized in that the gate terminal (Gate1) of the field effect transistor is connected to the source terminal (Source1) of the field effect transistor via the further capacitor, the third capacitor being connected in parallel to the working constant current source.