I have a confession to make. I've spent the last 4 years constantly engaged in programming and simple circuit building, and after all this time...I've never used a transistor in a circuit. It's not that I didn't want to, or that I didn't realize the critical importance of transistors, it was just that each time I investigated using one, I never fully wrapped my head around it and was able to use a relay in its place for the projects I was working on.
|Arduino with simple NPN transistor circuit driving LED.|
If using a transistor is second nature for you, the rest of this post will probably be fairly boring...but I thought it could help people like me who are working with them for the first time.