Ian Woofenden wrote in a message to Roy J. Tellason:
 IW> 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 the 
 RJ> array dark,  is a great deal more sensitive to damage to cells 
 RJ> than earlier tests.  A defect affecting one quarter of one cell 
 RJ> in a 40-cell string showed only 0.02 percent difference with 
 RJ> the older test methods, while measuring the capacitance showed 
 RJ> about a one percent change. The temperature coefficient of 
 RJ> gallium arsenide cells is given as being 5x10e-4 degrees C e-1.
 IW> How exactly do they measure the capacitance?
They mentioned the use of an R-L-C bridge,  that's one of a number of 
possible ways to do it.
 IW> ... Private industry focusses on researching products that
 IW> have a profit potential, that is, products that a great many 
 IW> people want. Government research ensures this prejudice is 
 IW> overcome so that products nobody wants will always be in ample 
 IW> supply.
Oh,  you noticed that too,  eh?     :-)
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