Abstract: An artificial intelligence based method and apparatus for locating faults in electronic units includes a technique for modelling electronic units in terms of behavioral constraints. Behavioral constraints model circuit components in terms of changes in outputs thereof which result from changes in inputs thereto. These changes, referred to as "phase changes" may be supplemented by gain and compliance constraints to model an electronic unit at all functional abstraction or hierarchical decomposition levels thereof. In addition to providing a universal modelling scheme, behavioral constraint relationships provide a highly accurate indication of subtle changes in a circuit, for accurate fault location or troubleshooting.Troubleshooting takes place by applying a predetermined search strategy on the electronic unit which is represented by behavioral constraints. The search strategy begins with a top down search.

Abstract: Apparatus and test film strip for evaluation of a film processor, particularly an x-ray film processor, based on a photodetector signal sequentially indicating the optical density of graded density test areas on a developed film and comparing the output thereof to a preselected voltage relating to the acceptable/too dark threshold of an unexposed or base fog area, the acceptable or too light threshold of a maximum density or dark area and the acceptable/too light and acceptable/too dark threshold of a medium density test area. Sequence testing of the graded density areas is functionally related on a single film strip to timing marks, adapted to be read by photodetector and timing circuitry, the timing marks and graded density test areas being linearly spaced and relatively disposed along the length of film strip.

Abstract: Apparatus and method for evaluation of a film processor, particularly an x-ray film processor, based on a photodetector signal sequentially indicating the optical density of graded density test areas on a developed film and comparing the output thereof to a preselected voltage relating to the acceptable/too dark threshold of an unexposed or base fog area, the acceptable or too light threshold of a maximum density or dark area and the acceptable/too light and acceptable/too dark threshold of a medium density test area. Sequence testing of the graded density areas is functionally related on a single film strip to timing marks, adapted to be read by photodetector and timing circuitry, the timing marks and graded density test areas being linearly spaced and relatively disposed along the length of film strip.

Abstract: A high frequency transistor ballast is utilized to drive flourescent lamps. The electrical system of the ballast consists of a central rectifying and control panel and a high frequency inverter. There is also provided a low energy switch in the high frequency inverter system controlling the operation of the high frequency transistor ballast.