A circuit for analog-digital conversion, which includes a first connection and a second connection and a third connection and a fourth connection for connecting a sensor, an analog-digital converter (ADC), whose first input is connected to the first connection and whose second input is connected to the second connection, a first current source circuit for outputting a first output current, a first switching device for the switchable connection of the first current source circuit to the first connection or to the third connection, a current source/sink circuit for outputting a second output current, a second switching device for the switchable connection of the current source/sink circuit to a reference potential or to the second connection, and a third switching device for the switchable connection of the reference potential to the second connection or to the fourth connection.