Ok, thank you. I am asking myself a lot of question because when advancing in my electronic learning (through the great Make : Electronic book), I see that there was a lot a false rules I was following with electricity / electronics.
When I had to replace a DC adapter from a device, I was always thinking that the current have to be respected, but in fact the only important thing to respect is the voltage (and the type of electricity of course).
If I replace a DC of 12v - 1000mA by a 12V - 2000mA won't pose any problem by example. The device will just use less current that what the DC can safely provide. Maybe replacing it with a 12V - 500mA will avoid a correct working of the device due to the lac of current.
Anyway, thank you for your help.