I've been learning more about voltage dividers, and I see a few different ones online. The idea is that I want big resistors so battery won't be depleted quickly, but big resistors prevent accurate analog voltage readings. So all of these 4 circuits have a capacitor in there to buffer that battery voltage, but which ones work, and why, and why might you want to add R3 into the circuit?
I'm still kind of learning about how it works, so trying to understand the why is important for me.
Ok...let's assume that I actually wired up a common ground. I was trying to focus on just the voltage divider circuit. There's also no power going to the microcontroller, etc...