The invention relates to an amplifier circuit (10a, 10b) for a two-wire interface, comprising a first current path (1), comprising a voltage-controlled current source (T1) having a gate (GT1), which is connected to an input connection (E1) of the amplifier circuit. A second current path (2) of the amplifier circuit comprises a voltage-controlled current source (T2), which is connected in series with the second resistor (R2). The first resistor (R1) and a parallel connection of the first and second current paths (1, 2) are connected in series between an output connection (A) and a reference voltage connection (B) of the amplifier circuit. The amplifier circuit (10a, 10b) makes it possible to adjust the gain and to provide a supply voltage and a useful signal over a common conducting track (L).