5V Regulated Power Supply: + to VIn or 5V Pin?

Hi Folks,

My apologies for the rookie-question - it's a short one, tho.

My project uses an Arduino Nano, which is powered by a USB power bank. Not via the USB connector on the Arduino, but by having the 5V +/- of the USB wire go to a proto board from which they also source other components.

I currently have the + of the 5V Power Supply connected to "VIn" on the Arduino - and everything works like a charm.

Hypothetically - would there be a (dis)advantage of connecting it to the 5V Pin instead?



With it connected to vin, what voltage do you measure on +5 pin?
If it is not 5 volts, I would connect the 5 volt power pack to 5+ directly.
Make sure you observe polarity.

On a pro mini you can connect an external 5 volt regulated voltage straight to +5 pin.

I'll measure it once I'm back home. The power-bank delivers something around ~5.05V when charged, and from the layout, nothing is sourced off the Arduino directly.

If you are putting 5 regulated volts directly into VIN the arduino will see less than that. Its going to drop as its goes through the regulator already on the nano. Will the arduino work? yes.. however it may be running at 4-4.5 volts. Going directly to the 5 volt pin will give the chip full power.

The arduino can run down to less than 3 volts if it is 8mhz. In my experience 16 mhz is good to just under 4 volts then things start going funny.

I would run the 5 volts into the 5 volt pin.

Thanks again for the advice here.

I've measured voltage between Gnd to 5V when attaching a regulated 5V supply to VIn, and got around ~4.05V - so I changed it, feeding directly into the 5V pin now. So that was definitely the better choice.