Abstract: The invention relates to a fiber optic measuring device for measuring physical and chemical quantities. Sensors positioned in the ray path influence the spectral composition of the light in dependence on the quantity to be measured. The sensors are of a material with an absorption edge or one or more filters of interference type.

Abstract: 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.

Abstract: The invention relates to a fiber-optically coupled measuring device which has an optically energized transducer section which produces signal information in an optical form, the energy supply for the transducer section and the signal information therefrom being transmitted via a light guide fiber. The signal information is transmitted to a receiver at a location remote from the transducer section, the signal information being modified in response to electrical signals fed to a light emitting component of the transducer section.

Abstract: The invention relates to a device for measuring current which traverses a light-emitting structure, the current passage thus causing emission of light. It is characterized in that the emitted light signal is adapted to be supplied to two photo-detectors having different sensitivity spectra and/or with at least one photo-detector being provided with an optical filter. The output signals of the photo-detectors are adapted to be supplied to a quotient forming member and/or a calculating member for obtaining a signal which is compensated for temperature variations in the light-emitting structure and other sources of error.

Abstract: A fiber-optic temperature-measuring apparatus which monitors the photo-luminescence of a body of solid material subjected to the temperature to be measured. Exciting radiation is conducted by means of at least one optical fiber towards a material with temperature-dependent luminescence which is in optical contact with the fiber, whereby luminescence occurs. The radiation emitted as a consequence of the luminescence is transmitted via at least one optical fiber from the body to a place of measurement, where a measure of the temperature may be obtained. The luminescent body may consist of a semiconductor material.