Ardunio uno dual source input about.

Hey All,

can i connect to 12V DC( jack input) and USB cable for pc to ardunio board at the same time? is it correct this connecting?

Yes.

Ok thank you so much.

On this page Arduino Uno Rev3 | Arduino Official Store, under documentation it states:

Power

The Arduino Uno board can be powered via the USB connection or with an external power supply. The power source is selected automatically.

Do read the documentation, there's other stuff of use to you!