I have high current usage For my circuit as you can see below (link):

enter image description here

I like to power Arduino when it is not connected to PC by USB Connection, So I want to add one external power supply and connect it's GND And 5V to Arduino GND And 5V pins.

So with this new circuit, I have two power supply for Arduino uno as you can see below: :

1-USB Connection to PC

2- Powering the Arduino by External Power Supply and LM7805

enter image description here

So I Asked here about connecting two power supply for Arduino (external power supply and PC USB Connection) and check this circuit Safeness for USB Port of PC or the Arduino.


  • I'm not exactly sure what you're asking. Jun 3 at 17:43
  • I don't see a problem with that. Should work
    – chrisl
    Jun 3 at 18:00
  • 1
    All you have done there is replicate the voltage regulator that is already on the Arduino itself. Seems a bit pointless to me. If you want higher current 5V then you should consider either a 5V supply (USB charger) or a switching regulator instead of linear. Otherwise you're really not achieving anything useful.
    – Majenko
    Jun 3 at 18:37
  • 1
    Thanks, @Majenko. the question is When i have USB connection and the second power supply, can I connect GND And 5V pins of the new power supply and the Arduino pins ( GND and 5V Pins) to each others?
    – so sa
    Jun 3 at 19:04
  • 1
    Sure you can. Just like the internal regulator is.
    – Majenko
    Jun 3 at 19:05

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