The basics of electrics - you only need supply the correct voltage; the load takes care of the draw.
Does a 10A AC supply blow a 1A radio etc; or a 100A battery supply blow a a 3W/250mA bulb?
You don't need to now "how the internals", all you need to know is its voltage and that you can supply or exceed the current required.
Sorry for the interrupt, but curiosity got the BETter of me. (I'm betting a 3-way wiki.)