Best guide to learning about the electrical side of things?

Hi guys. I have been vaping for 3 years now but I still don’t understand the electrical side of things. I know there are things that shouldn’t be mixed and matched. I know there are some tanks/coils that don’t work on some batteries. I don’t know why! I’d like to begin learning. I’d like to know enough to understand mods eventually. The people who build their own seem to be really happy.

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