The current goes from the blue wire through the fuse, then to a contact under "4" on the white thing, then through a capacitor into "1" and back out the white cord. "2" and "3" are also joined by a capacitor, with a black wire also on one end of the capacitor and an orange wire on the other that both go to the rest of the circuitry. What exactly is going on in that big white thing in the center and how does it effect the current flow? How does it relate "1" and "4" to "2" and "3", and what does that arrow mean?