Let me answer your power supply questions.
I have seen this many times that people do not
understand power supply ratings.
There are, basically, two types of DC power supplies:
regulated and unregulated.
The unregulated type is the simplest kind:
A rating of, let's say, 5 volts at 1 Amp means
exactly that. You can expect that you will
measure 5 volts at its output terminals when
it is delivering 1 Amp to a load. However, if
there is no load on that supply, there is no
voltage drop in its wires, so the terminal
voltage will be higher than 5 volts. That means
that the output voltage will change according
to how much current it is delivering to a load. How
much 'extra' voltage there will be is dependent upon
the quality of the unit.
The regulated type of 5 volt at 1 Amp supply is more
It has circuitry that works to keep the output voltage
constant, and corrects that according to the load current.
With no load, its output terminal voltage will be 5 volts.
(That is the easy way to tell is the supply is regulated.)
With a 1 Amp load, its terminal voltage will be very close
to 5 volts. So, the output of a regulated supply remains
quite constant while the load changes.
That having been stated, you can understand that a power
supply delivers a terminal voltage but the current it supplies
depends on what is connected to it as a load. A 1 Amp supply
can not deliver that current into a load that does not require
it. Ohm's law holds here, too, The output current is: terminal
voltage divided by the load resistance. No load, no current.
If you have another question, just ask it.