A sensor system includes a sensing element that includes a sensing material and electrodes configured to apply a first electrical stimuli to the sensing material at an electrical excitation frequency, a modifier assembly including one or more circuits configured to change an electrical impedance of the sensing element, and one or more processors configured to control the modifier assembly. Responsive to exposure of gas to the sensing element, the one or more processors change a linearity of a first electrical signal received from the sensing element by changing the electrical impedance of the sensing element and applying a second electrical stimuli to the sensing material at the electrical excitation frequency.

A method includes applying heat to a metal oxide sensing element of a gas sensor, varying the heat applied to the metal oxide sensing element for at least a time interval, and measuring an electrical resistance of the metal oxide sensing element versus variation of the heat for a time interval. The measurement of electrical resistance of the metal oxide sensing element versus variation of the heat applied to the metal oxide sensing element is compared to a set of corresponding reference measurements associated with a plurality of different target gases. A further sensor parameter versus the variation of electrical resistance and variation of the heat applied is measured to obtain a three-dimensional trajectory corresponding to variation of the sensor resistance, the variation of said heat and the variation of the further sensor parameter. This comparing includes comparing the trajectory in three dimensions to a set of reference three-dimensional objects.

An electronic device is disclosed. The electronic device comprises: a gas sensor having different sensitivities in temperature for each of a plurality of gases; and a processor for calculating a concentration of at least one of a plurality of gases on the basis of an output value of the gas sensor for different temperature sections.

A method for determining a nicotine content in a gas mixture. The method includes exposing a metal oxide-based sensor to the gas mixture, applying a temperature profile over time to the metal oxide so that the temperature of the metal oxide, proceeding from a predetermined first temperature level, is brought to a predetermined second temperature level under controlled first transition conditions, and the temperature is brought from the second temperature level to a third predetermined temperature level under controlled second transition conditions, ascertaining a transient specific electrical resistance of the metal oxide at at least one certain point in time during the application with the temperature profile, and determining the nicotine content based on the ascertained resistance. A processing unit and a computer program product for carrying out the method are also described.

A gas detector includes metal-oxide semiconductor gas sensors and their driving circuit. The gas detector stores the ratio of initial gas sensor resistance in air and that in an atmosphere including Freon gas, for the gas sensors. The gas detector learns sensor resistance in air for a gas sensor in use and detects Freon gas by comparing the sensor resistance of the gas sensor in use with the learned resistance in air divided by the ratio. When the first gas sensor has been used for a predetermined period, both the first gas sensor and a second gas sensor are used for a learning period to continue detection of Freon by the first gas sensor and to learn the resistance in air of the second gas sensor. After completion of the learning period, Freon is detected by the second gas sensor.

A gas sensor includes: a first thermistor having a resistance value that changes according to a concentration of a first gas with a first sensitivity and changes according to a concentration of a second gas with a second sensitivity; a second thermistor connected in series to the first thermistor, the second thermistor having a resistance value that changes according to a concentration of the first gas with a third sensitivity that is lower than the first sensitivity and changes according to a concentration of the second gas with a fourth sensitivity that is different from the second sensitivity; and a correction resistor connected in parallel with the first or second thermistor.

A resistive particle sensor is described for detecting soot in the exhaust gas of an internal combustion engine, including a sensor element having two strip conductors, which extend spaced apart in meanders in parallel to one another in an area of the sensor element that may be exposed to the exhaust gas, and a resistance strip conductor, the two strip conductors each being capacitively connected via capacitor elements to the resistance strip conductor.

A method for analyzing a gas, where a sensitive metal oxide-containing layer is exposed to the gas, includes: reducing the temperature of the sensitive layer from a first temperature to a second temperature, the temperature of the sensitive layer being maintained essentially at the second temperature for a predetermined time period; increasing the temperature of the sensitive layer to a third temperature; measuring at least one electrical resistance value of the sensitive layer while the sensitive layer exhibits essentially the third temperature; and analyzing components of the gas based on the measured at least one electrical resistance value.

A temperature-regulated chemi-resistive gas sensor includes a sensor surface including a chemically sensitive sensor layer including an active material for adsorbing and desorbing gas molecules of an analyte gas. A predetermined time-continuous periodic temperature profile is applied for periodically heating the sensor surface. An electrical sensor layer conductance signal is determined and time windows are applied to the sensor layer conductance signal. For one or more of the time windows, discrete frequency spectrum data of the sensor layer conductance signal is obtained, and a current gas concentration of the analyte gas is determined based on the obtained discrete frequency spectrum data.

A system and method for ascertaining the concentration of a preselected target substance, characterized by a mitigated tendency for yielding results distorted by a departure from a state of calibration, i.e., by “drift”, which drift is ordinarily caused by temperature and humidity variations; drift-mitigation is achieved by exposure of a target substance to a metal oxide semiconductor material, the temperature of a heating element operatively associated with said material being cycled between a low-temperature interval and a high-temperature interval, in which latter interval the material's temperature is raised to a level at or above the minimum temperature for rapid formation of one or more oxides of the target substance, the oxide formation taking place in a sufficiently short time that the conductivity is reflective of a transient signal amplitude in a brief interval of time, such that the external factors causing drift do not have sufficient opportunity to distort the concentration determination.