[RFI] Diodes in solar panels

Dennis Monticelli dennis.monticelli at gmail.com
Sun Jun 2 23:45:10 EDT 2019

FYI. Your typical panel contains anywhere from 3 to 6 diodes (three is most
common) wired in reverse across sections of the long series string of solar
wafers.  Under illumination the diodes are reverse biased and do nothing.
But if shade were to fall upon some of the wafers then the situation is
similar to a series string of batteries in which one battery is dead.  The
good cells try to push their current thru the bad cells with the bad cells
developing reverse voltage (chemical leakage and outgassing usually
results).  With panels the illuminated wafers will push their current
through the bypass path created by the diode(s) that sit across the shaded
wafers.  In doing so the entire panel doesn't get shut down by a few shaded

Could these diodes cause RFI? Probably not.  It's just a few more junctions
out of scores of them.

Dennis AE6C

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