ground-loop solved
RS_Jim
Posts: 1,753
I burned up a few boards because of a substantiel difference in ground potential with my powered usb hub (48 volts) and my computer which is powered through a three prong cord. I wanted to use the powered hub because a P2 board can get a bit power hungery when you start running multipel cogs and need to also.power servos etc. In my goodie box (read junk) I found an old radio shack 3 amp 12 vdc power supply with a cigar lighter jack on the front panel. A quick trip to the car netted an automitive usb power supply with 2.4 A capacity outputing 5 V from a usb female. A careful measurement of the grounds found no ground loops. I knew that old power supply would find ause somday.
Jim
Comments
Sounds like you are talking about the earth wiring in the building. You've probably got some unsafe wiring that an electrician should look into.
No, it has to do with two pin switching power supplies. Both computer and usb supply connected to the same three prong grounded outlet. Switcher has no ground reference. The solution works well, and is worry free.
Jim