Patent ID: 8268089

Claim:
A device for checking a concentration of clear rinsing agent in a rinsing liquid of a program-controlled water-carrying household appliance, the device comprising: a processing unit operatively connectable to a sensor having at least one transmitting element that emits an optical signal and at least one receiving element that receives the optical signal emitted by the transmitting element, the processing unit being operable to determine a wetting of the sensor with clear rinsing liquid and to render an estimate of the concentration of the clear rinsing agent in the clear rinsing liquid as a function of run-off behavior of the wetting of the sensor with the clear rinsing liquid, the processing unit determining the wetting of the sensor with the clear rinsing liquid and rendering an estimate of the concentration of the clear rinsing agent in the clear rinsing liquid based upon an energy level emitted by the transmitting element and received by the receiving element.