[amsat-bb] Spectra Lab UTJ cell testing???

[GEO Badger]

Bob,
I've played with all kinds of solar cells and I've never tried applying voltage to them without a blocking diode. Please keep us, at least me, up on any findings. ---  
 Ciao baby, catch you on the flip side.    
 GEO     

 http://www.w3ab.org

Time flies like an arrow, fruit flies like a banana.

      From: Robert Bruninga <bruninga at usna.edu>
 To: Amsat BB <AMSAT-BB at amsat.org> 
 Sent: Friday, February 23, 2018 3:04 PM
 Subject: [amsat-bb] Spectra Lab UTJ cell testing???
   
When you feed voltage into a UTJ Multi junction solar cell it emits RED
light all across the solar cell.

This is a good test to see if the cell is 100% involved or there are low
performing sections.

But I need to fully understand what is going on!!

Does this damage the cell?  How bright can it get?

My problem is that when I feed current into the solar panel to simulate
sun on the panel, the solar cells all light up and so some current is
being bypassed into the cells and not getting to the spacecraft.  Is this
damaging to the cells?

I have not been able to find any links to a description of this kind of
cell testing and limits.

Bob
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