Hello JayKool_56, All I know about the USB ports of PCs is that they only deliver 5V :-[ that's not very high to make a PSU ! And for the current, i don't know exactly but i think it might be 100mA. May this could help ...
Hi Shekhar, As said by audioguru, the neutral is effictively connected to ground in the transformer. This is made to allow the differential interruptors to work when a leakage appears in the circuit.