Abstract: A redundant power supply system with several individual power supplies, each connected to one of several power inlets. At least one power supply can be connected to a selectable one of the several power inlets by means of a steering network.

Abstract: Embodiments of the invention include a test circuit having an auxiliary low power test signal generator, filters, and a detector to test a power switch. The generator sends an auxiliary low power test signal having a different frequency than a power signal for the switch to an input of the switch. The detector detects the auxiliary low power test signal at an output of the switch. Test circuit filters are used to filter out the power signal from reaching the auxiliary low power test signal generator or the detector circuit. A circuit of the test circuit is tuned to the test signal's different frequency to ensure that the detector only detects the test signal when the switch is in one position. Thus, by detecting or sensing the test signal across the switch, the detector can detect whether the switch is operating properly.

Abstract: An illumination sensing and light level control system for an area of interest includes a light collector to collect and focus light from a relatively large portion of the area of interest, a light-sensitive array including a matrix of light-intensity sensitive elements for receiving light collected and focused by the collector, a multiplexer and signal conditioner for processing and digitizing the light intensity values, a microprocessor for processing the digitized data and controlling the operation and control functions of the system, and a controller for controlling the light level of one or more lamps or sets of lamps associated with the area of interest. A calibration device is used to generate the desired matrix values for comparison.