I'm trying to get .5 A of current from a mobile phone's DC adapter, which is within its rated specifications. I am able to detect a voltage of ~5 V DC between the power and ground wires, so it seems like the adapter's working. However, when I apply a load between the two wires, I can't detect any current flowing with my multimeter (it's set to mA, and the terminals are in the correct sockets). I've tried putting a rheostat in between (from 0-1 megaohms) the two wires, as well as a very fine nichrome (resistance) wire - no current flows in either case. Am I doing something wrong, or does the cell phone charger have some sort of safety mechanism built in that prevents it from supplying current to only the phone?
thanks