Chu Chu
I think part of the confusion is calling it square wave DC.
Totally agree, we argued that with the Boeing trainers but they weren't having any of it.
Waterfalls123 That schematic isn't completely accurate, lots of info missing from it so it doesn't tell the whole story. It doesn't show the 3rd ext power socket for a start.
But on the whole, yes, you've got the general idea right.