BALLOON-FLIGHT INSTRUMENTATION FOR SOLAR-CELL MEASUREMENTS

Instrumentation was developed which automatically measures the V-1 characteristics of a number of solar cells, and transmits the resultant serialized data stream over an RF telemetry link. The particular system was designed for 64 cells whose selection is accomplished entirely by semiconductor switching. Two-hundred-and-fifty-two points are taken on the V-1 characteristic, giving detailed information on slopes as well as actual values. Measurement accuracies are 0.03 percent of full scale for voltage, and 0.1 percent for current these do not represent attainable limits, but are simply reasonable limits for this specific application. The system described was built to calibrate solar cells on a high-altitude balloon flight, but the techniques can be used equally well for ground or satellite applications.