On Thu, Nov 20, 2008 at 17:24, DJDAS <[EMAIL PROTECTED]> wrote: > Cédric Berger ha scritto: >> I did not have a look at neo's circuitry. >> But whatever the method it uses, it cannot force 1A if 1A is not >> available (wall charger unplugged from the wall won't give 1A :-p ) ? >> > Uhm...not exactly true... Ohm Law says: V = R * I -> I = V/R, and if > R->0 then I->oo > In practice if you power a load with a little impedance (in real systems > the load is not always only resistive) the current requested will grow > and the source could be damaged (try to short circuit a normal battery, > you'll see a flash and if you maintain the circuit closed you'll meld > the battery). > This is why you should not ask 1000mA from the USB port (for example) > unless you're sure the hardware could give it. > Bye :) >
Yes but I also have some car adapters that "did not mind" being shorted (12v to 5v adapter, given for 350mA). So I doubt a device wanting 1A would be worst than a short circuit... but what would be the output in such a case I do not know. _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community