I have some level of basic electronics knowledge, but I am only just learning arduino and having a lot of fun. Quick question. If I am just playing around with simple things like "Attaching a led to a pin using a circuit board" do I need to turn off (unplug) the uno? It seems like I shouldn't have to, but I just don't know what I don't know
Play the odds: Every wire or diode or resistor you add to the breadboard gives you two chances to push it into a wrong hole. Do yourself a favor and switch off the power so you can double or triple check that before risking a goof up! (I have to do this because of my poor eyesight.)
I do it almost all the time. Have not had any problems with it.
Reminds me when I was working in a local radio station back in the 80's. The radio station did not have much money and the sound mixer was home made by someone who did not know how to solder properly. During a live sending we noticed that there was noise on one of the microphones.
It was possible to open the mixer at the top, so I opened it and saw that there was a bad soldering on the mic input. I turned on the solder iron and fixed it while they was talking in the studio