Abstract: Apparatus for determining the displacement or position of an object comprises a light source and a light receiver for receiving light transmitted from said light source, and a fiber optic conduit of Y-shaped configuration having the end of one arm thereof positioned adjacent said light source and the end of the other arm positioned adjacent said light receiver, said conduit arms forming a common bundle of optically conducting fibers in the base of said Y, some of which are transmitting fibers for conducting light from said light source to a surface of the object and some of which are receiving fibers for conducting light reflected from the surface of said object to said light receiver so that the conduit is normally objective to conduct light from said light source and to conduct reflective light impinging on an end face of said common bundle to said light receiver.

Abstract: An apparatus is disclosed for sensing rotational or angular position of a shaft. The apparatus incorporates two light transmission paths, each having a separate photodetector providing an electrical signal in response to the intensity of received light. The electrical signals from the photodetectors are differentially processed to obtain a signal representative of rotational position. Devices are provided in each of the light transmission paths to vary the intensity of light transmitted in the path, and these devices are mechanically coupled to the shaft so that the variations in the respective light paths are opposite. The differentially processed photodetector signals are therefore unaffected by the absolute position of the shaft but are responsive only to deviations from a reference position. Furthermore, this differentially processed signal exhibits a higher degree of linearity was heretofore obtainable. Various embodiments are disclosed for achieving this opposite variation in the respective light paths.

Abstract: An apparatus is disclosed for sensing rotational or angular position of a shaft. The apparatus incorporates two light transmission paths, each having a separate photodetector providing an electrical signal in response to the intensity of received light. The electrical signals from the photodetectors are differentially processed to obtain a signal representative of rotational position. Devices are provided in each of the light transmission paths to vary the intensity of light transmitted in the path, and these devices are mechanically coupled to the shaft so that the variations in the respective light paths are opposite. The differentially processed photodetector signals are therefore unaffected by the absolute position of the shaft but are responsive only to deviations from a reference position. Futhermore, this differentially processed signal exhibits a higher degree of linearity was heretofor obtainable. Various embodiments are disclosed for achieving this opposite variation in the respective light paths.

Abstract: A utility meter has a plurality of rotating shafts which have angular positions corresponding to the digits of a consumption reading. A cam is attached to that shaft which is associated with the least significant digit. The cam has a light reflecting track. Light from a light source is reflected off the track to a photodetector along an optical path which varies in length in accordance with angular cam position. Electronic circuitry is connected to the light source and photodetector and produces an output signal in digital form which has a frequency related to intensity of light incident upon the photodetector.

Abstract: A solid state power switch for gas discharge lamps is disclosed which is capable of providing a bipolar signal to a lamp and which substantially eliminates losses due to switching delays of internal devices. A timing control signal of a predetermined frequency and wave shape is provided to a pair of threshold comparators, which respectively receive a first and second threshold signal such as first and second reference voltages. The first comparator produces an output signal only when the timing control signal is below the first threshold signal and the second comparator provides an output signal only when the timing control signal is above the second threshold signal. The signals from the two comparators are used to control the on time of power switches of opposite polarity. Thus, the time that the control signal is between the two thresholds represents the switching delay interval.