Arduino power problem

hallo bro's...

need help.. it about pwer arduino..

iam newbie n need help.. i create project led chaser style and i uploaded sketch to board and it work fine. but everytime i remove/disconnect usb from arduino all led turn on (led chaser fail to work because all led on in same time) and if i connect usb cable to pc then led chaser normal n work fine.. i use arduino nano n use source power 12v 2a. i have 2 board arduino n all have same problem like that..

Schematic and code please.

My first thought it that with all the current drawn by those leds, and the 12V supply, you are overloading the regulator on the Arduino.

For this kind of circuit, a 5V power supply would be better. Split the + & - cables from the psu and take one pair to the 5V & GND pins on the Arduino and the other pair to the led circuit.

thanks for answer. but i use power 5v and 9v too but still same problem and still don't know why.. sorry my schematic or code skecth lost/unsaved and my pc use deepfreeze. i use skecth that i download form google.. i just little edited in void loop. maybe tomorrow i can show the project. iam not recorded yet.

A Nano on 12volt can't power ANY LEDs from the 5volt pin.

The onboard regulator will almost instantly overheat and shut down (if you're lucky).

Tell us what sort of LEDs you have connected to the Nano, and post a diagram/code showing how.
Leo..

thanks for u'r answer.. it already solved...is my bad.. i forgot use dioda to --> vcc.. work fine.. i usually always use dioda for power souce input for my project board.. thank you all

Any newbies finding this thread: please ignore bisaneothub's conclusion about what was wrong and how it was fixed. Total rubbish.