I am new to Arduino and thus need a bit of help.
I have made my own power supply for my projects from an ATX power supply I had as a spare.
The power supply works fine when powering my Mega 2560 and the projects. I use the +5V and Ground from the Power Supply. I have always used either the USB power source or the Power Supply via the DC input, never both at the same time( Only one plugged in at a time )
I decided I want to keep the power to the Mega on via the DC input while using the USB (Serial Interface). I decided to make sure there was no voltage across the two Power Supplies (Computer and ATX ) and was shocked to see 120V AC between the ground on the Mega and the Ground on my Power Supply
. I checked the DC voltage differance and it was 30mV.
Will it be safe to use the USB from my computer and the power via the DC supply from my Power Supply?
I am from South Africa and we use 220V
Thanks in advance