On Aug 20, 11:22 am, Richard Henry <pomer...@hotmail.com> wrote:

yeah I'm not sure either.... are you answering "can a device draw too
much current for itself?" and saying "yes" that it can?

Tell me, does current just depend on a devices impedance?  so I can
know how much anything is going to draw by just measuring the things
resistance and knowing the voltage I'm about to put across it?

I have keyboards and guitar pedals and such that all require 9V
adapters at different voltage ranges... so I can just buy a 9V adapter
which exceeds their current ranges... say the require 500mA and I buy
a 3AMP power supply.... then I should be good to go right?

but I guess this is my main question here: "can a device draw too much
current for itself?"

I try to build an analogy to all this stuff in my mind.... I picture a
board laying flat with some kind of jack on one side that lifts that
end making the board angled... on one end of the board I picture
marbles.... when the board is flat that is equivalent to no voltage
and the marbles dont move, if you raise on end of the board the
marbles start to flow down the board.... you are increasing the
voltage... and the marbles flowing is the electrons.... but my problem
in my analogy is that the electrons (marbles) are only present if
there is a device that wants them.... if there's no device then they
wont flow even if you lift the board... I guess you could put a little
door that slides up on one end of the plank or in the middle of the
plank and if its completely shut that's infinite resistance and as you
lift the door open and marbles pass under it you are decreasing your
resistance.... so the door only accepts the flow of marbles it needs
no more no less....