After starting to learn about parallel circuits I’m questioning my understanding of circuits in general. I attached an image of my basic circuit which from my understanding is parallel and works as I expect. However, it seems to me that if I wanted to add something additional into this circuit that involved a resistor it would add to the overall “total resistance” and wold lower the brightness of my LEDs. So I guess my confusion is in how you separate circuits so they don’t interact with each other if that makes sense.
For example if I use two separate pins on the Arduino to bring over 5v to two different bread boards I think I would be working with two isolated circuits with their own “total resistance”. How does this work? Is something like this possible in my circuit or would I need a separate power supply?