Power Supply for Arduino Uno via USB port

Hi all.

My project is using serial communication between my Visual Basic application and my Arduino Uno that I am using. It makes the arduino always have to be connected with the USB port of my PC.

So.. Do I still need to connect the arduino with the power from DC Power Jack (7-12V) or other input option? Or is it safe to only use USB connector as my arduino main source all the time? Thanks..

Note: I also conncet my Arduino Uno with Ethernet Shield on it if it matters

If the Arduino is not powering other stuff it would be OK.

If it has other devices connected you need to calculate how much current is needed. See "Detailed Power Considerations" HERE:

Also, some laptops, tablets and a few desktops do not put out a full 500mA and that may be a problem.

The Arduino UNO has a 500 mA 'polyfuse' that will protect your PC's USB port from overload. If you try to draw more than 500 mA the power will be cut off until you unplug the USB cable and plug it in again.

Except it is plugged in to Ethernet Shield, the digital pin is also connected to a servo that has its own external power supply 5V1A. What do you think? That's all the connectivity used to the arduino..

Thanks johnwasser, thats a good information to know :)

This is the connectivity of the servo to arduino I used plus its own external power supply

Some PCs may report a Surge event on the USB port and shut the port down, and it will stay down until the PC is reset.
I had this happen on a Lenovo recently, the PC didn’t like external 5V supplied when USB power was connected via an FTDI Basic, reported a surge and disabled the port. So I made a FTDI extender cable with the VCC wire having a connecter in the middle so I can disconnect the VCC line when the board is powered from its own DC-DC adapter, and I can still access the serial port of the uC for downloads and debug via print statements.

I use the USB port (next to DC power jack) on my arduino uno to connect to the USB port in the PC.

Does it count as a ftdi as well?

Cause from what i just googled, ftdi convert the connectivity from usb to several pin like vcc, gnd, rx, etc while I use cable that connect straight to the USB port.
Sorry if Im misundertanding…

usb port arduino uno.png