Abstract: In a biosensor system for detecting trace compounds resulting from a fire or from plants damaged by destructive insects, a live chemoreceptor is provided for sensing the trace compounds, and a semiconductor component is connected to the chemoreceptor for providing sensor signals when the chemoreceptor senses the presence of trace compounds.

Abstract: To eliminate the effects of semiconductive sensor aging in the use of a semiconductive sensor for measuring the state variables of a gas in a system in which a pair of electrodes are embedded in an active semiconductive layer so that the conductivity of the semiconductive layer varies as a function of the state variable, a field electrode is provided and superimposed upon the measurement voltage, a voltage pulse is applied intermittently and the characteristic of the resulting current pulse is used to compensate for changes resulting from aging of the sensor.

Abstract: A gas sensor arrangement has at least a first sensor element which is primarily sensitive towards oxidizable gases and generates a corresponding measuring signal and an electric control and evaluation unit, wherein the measuring signal generated by the first sensor element is evaluated. In order to avoid inaccuracies when in addition to the oxidizable gases at the same time also reducible gases are present, the gas sensor arrangement is provided with at least one second sensor element, which is primarily sensitive to reducible gases and generates a corresponding measuring signal, which is fed to the control and evaluation unit for evaluation.

Abstract: A sensor for determining and/or measuring alcohol which exhibits an electric conductivity which varies with the alcohol concentration, comprises a heater with a metallic-oxide semi-conductor body located in the range of the heater. A pair of opposite polarity electrodes are biased into engagement with the surface of the body by a spring clamping means. The semi-conductor body comprises a zinc oxide having a density which is close to the density of a monocrystal. The semi-conductor body is formed of zinc oxide and then sintered at a temperature above 750.degree. C and preferably at 1000.degree. C.