The sensor has a laser structured metal oxide layer formed on a substrate. The metal layer is structured so that at least two electrodes interleave in comb form and their outer sections are enclosed by heater structures. The electrode terminals for both electrodes (4, 5) and heaters (1, 3) are located at the corners of the substrate. Several arrangements can be provided on the substrate next to one another. Connections for the heating system can be located in the external edge of the substrate and at least at two points the heater resistance can be adjusted by laser cuts.
