Can an Arduino power a USB device like a tablet from one of it's pins or do I need a relay? I want to essentially have the Arduino turn on and off a USB charger. Thanks

  • 1
    USB is 5V, not 3.3V. Also, no. 40mA is nowhere near enough for a typical USB device.
    – Majenko
    Jan 28, 2020 at 23:25
  • do not use an arduino as a power supply
    – jsotola
    Jan 28, 2020 at 23:37
  • Any advice on how to do this then? Thanks Jan 28, 2020 at 23:55
  • use a mosfet instead of a relay; simpler, cheaper, lower power waste. google mosfet as a switch
    – dandavis
    Jan 29, 2020 at 0:10

1 Answer 1


If you already have a 5V source then you can use a MOSFET as a switch to turn on/off the power to the tablet like this: enter image description here

But if you want to turn on/off a USB charger that goes to an AC outlet, then you will need to control a relay to turn on/off the AC supply to the USB charger. You can use a relay module like this: https://www.amazon.com/Tolako-Arduino-Indicator-Channel-Official/dp/B00VRUAHLE

enter image description here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.