I'm VERY new to EE and am learning the basics. My first goal is wiring up some small lights for my son's LEGO projects, and am trying to sort out the basics here.
Right now, I'm attempting to piece together a mental model of how wiring up several LEDs work, mostly vis-a-vis attaching them to an Arduino. I've run into several hurdles here (seemingly a simple project) and keep coming back to the simplicity of a small strand of fairy LED lights.
The output of the Arduino is 5v. I'm comparing it to a strand of fairy lights I have which take 4xAA Batteries, for a total of 6V.
I've read the following:
- A white LED needs about 3V to operate, and requites around 20mA of current to have decent brightness.
- Each pin of the Arudino can only output safely 20 or 30mA. Thus, I can only safely run 1 LED, maybe 2 if I'm feeling risky, per pin on an Arduino.. Even if they're in parallel.
- AA batteries can output about 50mA constant current.. 4 AA batteries would be 200 mA, no?
- At the same time, this little pack of fairy lights on 6V can run like 50 white LEDs with no resistor as near as I can tell.
So how does the magic of the fairy lights actually work? What am I missing? Why is it that trying to wire up 6 little LEDs to my son's LEGO house is apparently going to require six separate pin connections, each with a resistor, etc.