> > On Aug 20, 7:27 am, "Bob Eld" <nsmontas...@yahoo.com> wrote:

> > > "panfilero" <panfil...@gmail.com> wrote in message

> > >news:8fa5a24f-9d8d-465a-9d73-605f64a48c71@c65g2000hsa.googlegroups.com...

> > > > I just had a couple of questions about current... can I device draw
> > > > too much current for itself?  I mean... if I hook up a device that
> > > > uses 1amp to a power supply without a current limiting control will
> > > > that device just use what it needs?  So basically will a 12V  2Amp dc
> > > > power adapter work for all devices that require less than 2Amps?

> > > Yes

> > Which question are you nasering?

> 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....