The invention relates to an electronic circuit for converting a charge signal of a WIM (Weigh-in-Motion) sensor 3, that is installed in a roadway 6 and has a charge signal output and a ground output, into a voltage signal. The circuit comprises a charge amplifier having an IC1 that has a first and a second input as inputs of the sensor 3. The circuit also comprises an integrated impedance converter (IEPE) at the output to a two-core cable 5 having a voltage signal output "OUT" and a ground output "GND". According to the invention, a capacitor (Cc) is connected in series to the charge signal output "In" of the sensor 3 at the first input of the IC1 of the charge amplifier for decoupling the internal DC voltage of the circuit via the sensor 3. Furthermore, a Zener diode D is arranged between the ground output "GND" of the sensor 3 and the second input of the IC1, which diode can be fed through a resistor R1, together with a current source 8 arranged at the output side, via the two-core cable 5 in order to adjust the potential at the second input of the IC1. In particular, the ground output of the sensor is at the same potential as the ground output of the two-core cable 5.