Hello friends, I've bougt my new Arduino UNO and I recived it two days ago. Now I'm doing some basic circuits to check all is right and to learn about the connections of arduino.
But I have a problem... with a basic circuit. It's a circuit feed by the pins 5V and GND of arduino. The circuit is the typical resistance (220) - switch - LED connected in series in a protoboard. It's weird because when I connect arduino without the circuit to the PC by USB it's all right but if I connect the arduino with the circuit between pins 5V and GND it's like if arduino were switched off... all LEDs (included ON LED) are off... I think it's a problem with connections or some like this but I'm worried about the integrity of my arduino. Thank you for your responses.
You short circuited your arduino with whatever circuit you built.