On (27 Dec 96) Roy J. Tellason wrote to All...
 RJ> I just stumbled across a rather interesting short article in
 RJ> the July 1996 issue of NASA Tech Briefs,  which describes a
 RJ> method for testing solar cell arrays.
 RJ> It seems that measuring the capacitance of the array,  with
 RJ> the array dark,  is a great deal more sensitive to damage to
 RJ> cells than earlier tests.  A defect affecting one quarter of
 RJ> one cell in a 40-cell string showed only 0.02 percent
 RJ> difference with the older test methods, while measuring the
 RJ> capacitance showed about a one percent change. The temperature
 RJ> coefficient of gallium arsenide cells is given as being
 RJ> 5x10e-4 degrees C e-1.
How exactly do they measure the capacitance?
... Private industry focusses on researching products that have a profit
potential, that is, products that a great many people want. Government 
research
ensures this prejudice is overcome so that products nobody wants  will always
be in ample supply.
--- PPoint 1.96
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