Asea Aktiebolag

Sture Goransson

Morgan Adolfsson

Torgny Brogardh

Christer Ovren

Bertil Hok

The invention relates to a measuring device for measuring physical and/or chemical quantities, comprising a measuring transducer and an evaluating electronic unit interconnected by at least one light-conducting fiber, said evaluating electronic unit comprising one or more light sources for transmitting light via said fiber/fibers to at least one sensor element, forming a part of said transducer, said evaluating electronic unit also comprising one or more light detectors for detecting light emitted from said sensor element(s). The invention is characterized in that said at least one sensor element possesses a non-linear relationship between the incident light intensity illuminating the sensor element and the intensity of the light emitted from the sensor element, that said light source/light sources are arranged to emit light having at least two, non-identical light intensities, and that at the same time said detector/detectors are arranged to measure the light coming from the sensor element.

Fiber optical measuring device, employing a sensor material with a

A capacitive transducer indicates the value of a physical quantity to be measured and is constructed with two spaced electrically conducting plates movable relative to one another in response to a mechanical signal representative of the physical quantity to be measured to generate an electrical signal in response thereto with the transducer capacitor being actuated and de-actuated to be respectively responsive and non-responsive to the mechanical signal in accordance with pre-designated time intervals. The electrical signal in accordance with the capacitance of the transducer capacitor is integrated to provide an output signal when the integrated signal exceeds a reference value.

Integrated capacitive transducer

The invention relates to an optical measuring device for measuring physical or chemical quantities which device employs at least one light source, such as a light-emitting diode, in optical connection with a sensor, the spectral properties of which (e.g. the absorption or luminescence spectrum) are adapted to be changed by the quantity being measured, and at least one light detector (e.g. a photo-diode or a photo-transistor) for receiving the output signal from the sensor. The invention is characterized in that the measuring signal is adapted to be obtained by spectral analysis, and that this spectral analysis is adapted to be performed by varying the spectral distribution of the light source (the light-emitting diode) or maintaining said distribution constant, and/or by varying the sensitivity spectrum of the light detector or maintaining said spectrum constant, and that this control of the emission spectrum and the sensitivity spectrum is adapted to be carried out by a periodic controlling of the temperature of the light source and of the light detector, respectively.

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Vaster.ang.s, Sweden

Sture Goransson