According to one embodiment, a gas sensor includes a film structure including a gas sensitive film and a heater film heating the gas sensitive film, a physical quantity sensing section sensing a predetermined physical quantity which varies based on storage of a gas to be carried out by the gas sensitive film, a voltage generation section generating a first voltage for heating the gas sensitive film at a first temperature and a second voltage for heating the gas sensitive film at a second temperature higher than the first temperature, and a voltage switching section switching between the first voltage and the second voltage to be supplied to the heater film.

An apparatus for measuring a concentration of a target gas includes: a gas sensor including a sensing layer having an electric resistance that changes by an oxidation reaction or a reduction reaction between gas molecules and the sensing layer; and a processor configured to, in response to the target gas being introduced along with air into the gas sensor, monitor a change of the electric resistance of the sensing layer and determine the concentration of the target gas by analyzing a shape of the change of the electric resistance.

Disclosed herein is a method of providing a structure having two electrodes connected by nanowires, exposing the structure to an analyte that can adsorb onto the nanowires, and passing an electrical current through the nanowires to heat the nanowires to desorb the analyte. Also disclosed herein is an apparatus having the above structure; a current source electrically connected to the electrodes, and a detector to detect the analyte.

A gas sensor and the drive circuit for the sensor are installed within a mobile electronic device. The gas sensor is intermittently heated to an operating temperature for detecting gases and kept at an ambient temperature for other periods. When a sensor of the mobile electronic device detects that the device is placed in a closed space, the heating of the metal oxide semiconductor is halted. When the sensor detects that the mobile electronic device has been taken out from the closed space, the heating of the metal oxide semiconductor is resumed. The poisoning of the gas sensor by siloxanes or the like is prevented.

We disclose herein a method for testing a batch of environmental sensors to determine the fitness for purpose of the batch of environmental sensors, the method comprising: performing a plurality of electrical test sequences to the sensor inputs of the batch of environmental sensors to measure electrical responses of the sensor outputs of the batch of environmental sensors; correlating the measured electrical responses from the batch of environmental sensors to predetermined environmental parametric ranges of at least one environmental sensor so as to define correlated electrical test limits; and determining the fitness for purpose of the batch of environmental sensors if the measured electrical responses are within the correlated electrical test limits.

A gallium nitride-based sensor having a heater structure and a method of manufacturing the same are disclosed, the method including growing an n-type or p-type GaN layer on a substrate, growing a barrier layer on the n-type or p-type GaN layer, sequentially growing a u-GaN layer and a layer selected from among an Al.sub.xGa.sub.1-xN layer, an In.sub.xAl.sub.1-xN layer and an In.sub.xAl.sub.yGa.sub.1-x-yN layer on the barrier layer, patterning the n-type or p-type GaN layer to form an electrode, forming the electrode along the pattern formed on the n-type or p-type GaN layer, and forming a sensing material layer on the layer selected from among the Al.sub.xGa.sub.1-xN layer, the In.sub.xAl.sub.1-xN layer and the In.sub.xAl.sub.yGa.sub.1-x-yN layer, wherein a HEMT sensor or a Schottky diode sensor can be heated using an n-GaN (or p-GaN) layer, thus increasing the sensitivity of the sensor and reducing the restoration time.

A method for operating a gas sensor device, which is equipped with at least one gas-sensitive electrical sensor resistor, a heating element for the controlled heating of the sensor resistor, a detection element for detecting the resistance value of the sensor resistor, and a signal processing element for processing measuring signals. In the method, measurements are carried out in time intervals, in which the resistance value of the sensor resistor is detected as a measuring signal, and the sensor resistor is heated for each measurement, the heating element being operated discontinuously in heating intervals and each measurement being assigned a heating interval. Measurements are automatically carried out in predefinable time intervals, and additional measurements are initiatable at arbitrary times. The duration of the heating intervals assigned to the individual measurements being selected as a function of the time interval to the preceding heating interval.

Disclosed herein is a gas sensor that includes a gas sensor part including first and second thermistors connected in series, a temperature sensor part configured to generate a temperature detection signal, a variable resistor connected in parallel to the first thermistor, and a control circuit configured to change a resistance value of the variable resistor based on the temperature detection signal.

A method of reducing power consumption in portable devices includes providing a sensor producing a sensing signal indicative of sensed entity and powering the sensor. Powering the sensor includes providing a first power value for a first time interval, providing a second power value for a second time interval, the second power value being different from the first power value, and discontinuing powering for a third time interval.

A method is suggested for determining an absolute gas concentration. The method employs a gas sensor arrangement comprising a gas sensor (1) and means (11, 12) for decomposing a gas to be measured. Furthermore, the method comprises the steps of acquiring a first sensor signal and determining from the first sensor signal at least one initial data point. Then the gas to be measured is decomposed using the means (11, 12) for decomposing the gas of the gas sensor arrangement. A second sensor signal is acquired and from the second sensor signal at least one decay data point is determined. Finally, an absolute gas concentration is determined from a gas concentration function by evaluating the gas concentration function at least for the initial data point and the decay data point.