Another way to think of this is math. The independent values are Voltage and Resistance.
The current flow depends on them.So,
Current = Volts / Resistance
where R is provided by the device being powered, and V out is provided by the wall wart. The current that flues is DEPENDENT on the two values (V & R). Truth is, the current may well be dynamic, and usually less than rated by the device.
While we can re-write this equation a variety of ways, useful when we know only 2 of the values and need the third, in practice this is how we treat wall warts and most power supplies.
I read this:
12V, 1A
in this way:
"I will supply at least 12V so long as my current rating of 1A is not exceeded."
The current flow depends on them.So,
Current = Volts / Resistance
where R is provided by the device being powered, and V out is provided by the wall wart. The current that flues is DEPENDENT on the two values (V & R). Truth is, the current may well be dynamic, and usually less than rated by the device.
While we can re-write this equation a variety of ways, useful when we know only 2 of the values and need the third, in practice this is how we treat wall warts and most power supplies.
I read this:
12V, 1A
in this way:
"I will supply at least 12V so long as my current rating of 1A is not exceeded."