Uno's behavior on Led 13

Hi! I have a question regarding Arduino Uno R3.

I noticed that if I upload Bare Minimum Sketch on the Uno R3, the led on pin13 (on board) is lit. If I upload AnalogReadSerial sketch, the led is still lit. But if I upload blink sketch, everything is normal, blinking as it should. Also, if I attach an external LED on pin 13 to GND and upload bare minimum, led on the board turns OFF.

I also notice that if I attach a shield on the Uno, the LED 13 (on board) turns OFF. I tried measuring the output voltage on pin 13 when nothing is attached to it, I get 0.7 V more or less, while on the other pins, readings are almost 0V.

I tried replacing the atmega328p on the Uno, and burned bootloader for Uno, still, the same behavior exists..

Is this normal on all Arduino Uno R3?I got this board from official distributor in our country. Please enlighten me. thanks!

Hello,

iamwin:
Is this normal on all Arduino Uno R3?

Yes.

Please enlighten me.

First spend a few minutes searching the forum. The subject has been discussed ad nauseam.

thanks again! :slight_smile: