I am new to electronics and arduino in general. I need to split a power supply in gnd and voltage. Basically, the power supply has one single wire (with the voltage and the gnd passing through it i think), and I need them to be separated. Sorry if this is a noob question, but I am really new to this whole thing.
If the cable of the power supply contains voltage and gnd, it's two cables, with a layer between them.
On the inside they look much like coaxial cables, so if you softly cut the outer shell(A) you maye see a mesh of blank wires(B,C,D), they're gnd in most cases. There also is an inner wire(C) which you have to cut softly, too. That's the voltage carrying wire(D), in most cases. (If it's approx. less than 10 Volts, check with a LED.)