Solid electrolyte sensor

A solid electrolyte sensor device for determining gas concentrations in measurement gases, with a sensor formed by a solid electrolyte which is arranged between at least two electrodes. The electrodes are permeable to gas and at least one of the electrodes faces the measurement gas. An electrical device is also provided for detecting and processing concentration-dependent sensor output values. For the purpose of permanently preventing disruptive adsorption of measurement gas components on the sensor or on the corresponding sensor electrode, an adjustable oxygen source is arranged in the vicinity of the sensor electrode which faces the measurement gas so that oxygen or oxygen radicals can be introduced into the measurement gas via this oxygen source for the oxidation of the measurement gas.