i want to build a simple circuit on a circuit board with a LED and one or two resistors and therefore i need a voltage source. Since I only have got a 12VDC - 9Vblockbattery adapter, i wanted to use my arduino uno to transfer the current to my circuit board. But I dont know which pins i should use and im afraid of doing it wrong and destroying sth (im a total beginner and do not have much experience with arduino).
I already tried connecting the GND pin of POWER with the -strip on the circuit board and the 5V pin of power with the +strip and it actually worked. I still do not quite understand what the 5V pin does, thus i dont dare to use this longer than a few seconds without the confirmation that im doing nothing wrong of someone with more expertise than me.