초록 ▼

A gas sensor, suitable for use under non-steady state conditions, has a gas-sensitive resistor with pairs of electrodes which either have different spacings between the electrodes of a pair, or comprise a pair at the active surface and further pairs buried in the resistor at different distances from

A gas sensor, suitable for use under non-steady state conditions, has a gas-sensitive resistor with pairs of electrodes which either have different spacings between the electrodes of a pair, or comprise a pair at the active surface and further pairs buried in the resistor at different distances from the active surface. The sensor can be used in place of a sensor array, and is coupled to a processor for processing the resistance signals to detect and/or measure at least one target gas. The sensor is self-diagnostic, and factors such as relative humidity and ambient oxygen, that can otherwise affect the readings, can be compensated for without the aid of additional sensors for that purpose. An operating line or surface is defined for the expected behavior of the sensor, and the resistance signals from the electrode pairs are processed so at to give information which is then related to the operating line or surface, so as to reveal, in terms of error indications, any malfunction of the sensor and/or the presence of specific constituents of the gas mixture.

대표청구항 ▼

[ I claim:] [1.] A method of analysing a gaseous medium using a multiple-electrode resistive gas sensor of solid state semiconductor material comprising a resistor having an active surface and a plurality of pairs of electrodes, disposed on said resistor, each pair of said plurality of pairs of elec

[ I claim:] [1.] A method of analysing a gaseous medium using a multiple-electrode resistive gas sensor of solid state semiconductor material comprising a resistor having an active surface and a plurality of pairs of electrodes, disposed on said resistor, each pair of said plurality of pairs of electrodes being different from each other pair of said plurality of pairs of electrodes as regards the spacing between the electrodes of the pair or the geometric orientation and disposition of the pair within the resistor relative to the active surface, the gaseous medium containing at least one target gas capable of causing electrical resistance of the sensor to vary in response to concentration of that gas, the method comprising: taking a resistance signal from each electrode pair with the sensor exposed to the gaseous medium; processing the signals to produce measurements therefrom; and relating the said measurements to a defined operating line or surface so as to determine, by deduction therefrom, a plurality of items of information, with the concentration of each target gas to be detected representing a separate said item of information, the number of electrode pairs being at least equal to the number of items of information to be obtained.