I have IR sensor with current draw 100ma i have to connect 5 of them is i can connect all 5 with arduino directly or i have to use external power suplly for them

  • what sensors exactly? Can you post a link to a datasheet?
    – MichaelT
    Commented Nov 3, 2019 at 0:50

1 Answer 1


An Arduino UNO has a max current of 20 mA per IO Pin and a max current of 200 mA of all Pins together. If you intent to drive the senders with the pins then this is impossible.

If you power the Arduino with USB, the VCC current is limited to 500 mA (thermo fuses). If you power it externally, it depends on the power supply. Using the voltage from the Vcc Pin is risky (IMHO), because the Arduino needs power too.

So with 100 mA per sensor I would definitively use an external power supply.

  • Can you please help which power supply i have to use soo that i can give supply to arduino as well as to my sensor externaly (becoz there is no use of give usb power to arduino if i am connecting external power for sensors ) i want to do it with single power source Commented Nov 2, 2019 at 17:31
  • I fear, I can not help you, as I know nothing about your setup. And it is also not a good idea not ask a question and than extend it again and again and .... So please ask a new question eventually with a link to this one. The more information you add to the question the more help you will get. Which Sensors do you use (give a link to the data sheet). How are they used. Are they all active at the same time, or just one or a few. Have you searched the internet for similar problems? Or edit this question, but add the details I suggested. (But do not add the details to a comment.) Commented Nov 2, 2019 at 17:52

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