I've often seen devices with power requirements specified only in Volts (e.g. 7-12V) but never the amperage. I've wanted to run various embedded devices of wall warts and batteries (the devices have regulators don't worry) however I've been hesitant because I'm not aware of the amperage requirements for the devices.
My question is: Is there a standard amperage that is "understood" for microcontrollers and the like?
I have been told that amperage doesn't matter however I beg to differ, since I am quite sure that if I supplied a 7-12 volt device with 9 volts at 1 billion, amps that it would explode.
EDIT: To put it simply. A power supply is rated at the amps that it will tolerate before overheating and taking damage?