[Lab] AC adapter question

Andrew O'Malley aomalley at gmail.com
Thu Jul 11 21:20:14 EDT 2013


The 7 amp calculation is correct.  Try to find a 5V @ 10A supply and you
should be good, assuming the circuit is as you described.  The one you
linked to is 26A which is a bit overkill (though nothing wrong w/ using it,
it will only supply the amount of current required by the circuit).

>>> Maybe I'm drawing too much Amps.  Would you recommend this AC converter

> >>> over the last one:
> >>> http://www.digikey.ca/product-detail/en/LS150-5/285-1817-ND/1918828
> >>>
> >>> I would have Amps to spare on this one.
>



> Your LEDs have a forward voltage of 1.6 volts and you are supplying 5
> volts,  leaving 3.4 volts for the 91 ohm resistor. Ohms law: current =
> volts / resistance. Plug in the numbers and you get 0.037 amps per LED,
> much less than the 0.250 amps that the resistors are rated for. The total
> current would be 7 amps, which is more than your supply is rated for.
>
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