Abstract: The invention provides a filter of the Fabry-Perot interferometer type for electromagnetic radiation having spectral density that is modified by a gas. The filter comprises a body which is transparent to said electromagnetic radiation, at least in its part through which the radiation passes. Said part comprises at least two portions possessing two facing surfaces that are mutually parallel and substantially plane. A "first" one of said portions is movable in a direction that is substantially perpendicular to the pair of facing surfaces. The filter further comprises: means for moving said facing surfaces between two extreme positions under the action of an electromagnetic field, and means for limiting adhesion between said surfaces in at least one of said positions in which said surfaces are at a distance apart which is small compared with the mean wavelength of the radiation passing through them.

Abstract: The flow rate sensor is made from a silicon substrate (1). A first face (A) of the substrate is provided with a heating element (2) disposed in a first region (R1) and with at least one thermometer component (4) disposed in a second region (R2), the first and second regions being insulated from each other by a third zone (R3) of oxidized porous silicon. According to the invention, the sensor is adapted to receive the flow of fluid (E) over the second face (B) of the substrate (1), with the first and second regions (R1, R2) forming respective thermal short circuits between the first and second faces (A, B) of said substrate.

Abstract: The invention relates to sensors having field effect semiconductors. The sensor of the invention comprises a ring oscillator constituted by an odd number of CMOS inverters disposed in a zone sensitive to the physical property to be measured. In order to increase the sensitivity of the sensor, the N channel of the NMOS transistor in each CMOS inverter is disposed perpendicularly to the P channel of the PMOS transistor.