Why does this device need an OR-Gate?

The device listed at the link below automatically switch the output
between either a 12V (really 13.8V) power supply or a battery depending
of if the power supply is on. It says it "uses two 80 ampere Schottky
diodes connected as an OR-Gate to isolate the battery and power supply
from each other." My question is what is the or gate used for? I
understand to diodes to stop the Power supply from sucking power out of
the batteries when it is off, but have on idea what advantage an or gate
would give.


http://www.powerwerx.com/product.asp?ProdID=2047&CtgID=3574


--
Chris W
KE5GIX

"Protect your digital freedom and privacy, eliminate DRM,
learn more at http://www.defectivebydesign.org/what_is_drm"

Ham Radio Repeater Database.
http://hrrdb.com

 

I just read that again. I thought it said 2 diodes connected to an or
gate. When it really says 2 diodes connected "AS" an or gate. I get it
now. Never mind.

--
Chris W
KE5GIX

"Protect your digital freedom and privacy, eliminate DRM,
learn more at http://www.defectivebydesign.org/what_is_drm"

Ham Radio Repeater Database.
http://hrrdb.com

 

It is just two diodes in series with the two power sources, one from the
battery and one from the power supply. The cathodes of the diodes are
connected together forming the output. This way current flows from the
source with the highest voltage. Logically that is an "or" function. It is
one "or" the other. If the two sources are the same voltage, both would
supply current.