My multimeter is going nuts and giving me jumping readings in about the 13 volt range but never stays a solid reading. And I get the same readings attaching the probes to either wires. I simply can’t tell the polarity difference on the two leads after I snipped the barrel connector off.
I looked at the power supply and it shows that the inside connector of the barrel connector is positive.
I am trying to wire that 72 W power pack into a power distribution board. Haven’t worked much with DC. Does it matter in this case?