I'm really new at this, and here is my doubt. What if I need to light 120x WS2812B (5v)LEDs (link: LEDs) using an Arduino Nano? if it takes 60 mAh each pixel, the total amount needed should be around 7,200 mA.

Could I use the same 5V/ 8A power supply (PowerSupply) for the Nano board and lights? Is that possible?

Thanks in advance, and sorry my ignorance on this area.

  • 1
    Check your units. Charge (e.g. in mAh a unit of electrical capacity, or how much current can be supplied over a given time). Current is the rate of charge flow (e.g. in mA). As written your question does not make sense.
    – MichaelT
    Apr 29, 2019 at 15:22

2 Answers 2


Yes, 120 LEDs * 60 mA = 7200 mA = 7.2A

An Arduino Nano will use 19 mA (Arduino Nano Tech Spec). Of course, if you add a power LED, or other components it will add, but it will likely be less than a few 100 mA. So that totals to max 7.4A.

It's always good to have some headroom which is 0.6A in your case (that's enough).

Actually what's happening is as follows: - Your 8 mA gives the current the components request - Your Nano requests 19 mA - Your LEDs require 7.200 mA.

As long as the voltage is the same (5V for both the LEDs, Nano, and adapter), and the components do not request more than 8 A summed up (with some headroom), the adapter will deliver the current needed. If all components request more than 8 A, than high likely the adapter will break (and possibly the attached components too).

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    Thanks Michel, I just wanted to make sure that I don't burn the board on my first attempt ;)
    – juasmilla
    Apr 29, 2019 at 15:24
  • You're welcome .. .you can wait for more answers, if an answer is helpful, upvote it, if the answer answers your question in a satisfactory way, accept the answer. Apr 29, 2019 at 15:27
  • @juasmilla, why would you think that you would burn the Nano? .... how are you planning to connect the LEDs?
    – jsotola
    Apr 29, 2019 at 15:43

It can supply both, as long as they are supplied separately; the LEDs must not be supplied through the Nano board, but connected directly from the power supply.

  • Fine, connecting the ground on both I suppose... Thanks for all your inputs! brilliant Arduino World, and of course, its community!!
    – juasmilla
    Apr 29, 2019 at 15:48
  • @Yes connect ground together Apr 29, 2019 at 15:50

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