Moving Power from USB B connector to DC power at the same time...

So I was wondering if it will damage the Arduino (Uno) by connecting up the DC input while the power from the USB B connector is still connected. I was envisioning the circumstance where, after uploading the sketch into the Uno (via the USB B connector), to keep the program running and needing to disconnect the USB connection, is it okay to connect the DC (I don't know the name of the DC connector- it's round with a positive center pin), then disconnecting the USB to keep the program alive and kicking.

Thanks for your opinions.....

I guess some people are scratching their heads asking, "how much of a noob can you be?"......my concern is that if you have the USB B connector plugged in, then concurrently plug, say a 12V supply into the DC plug, will this cause any hardware issues or problems?

There is generally no issue with doing what you want as far as using both the USB and the power jack.

Caveat seems to be to keep it under 10 volts on the power jack if its a REAL Arduino as they are quite prone to power regulator failure nowadays.

Clones seem much more tolerant in that department.

If I need to do what you suggest I connect the USB and then the power jack and then upload to the Arduino before removing the USB connector in that sequence.

The board is capable of switching as it needs.

Thank you sir! I am still new to the Arduino world...every little bit helps!