When we were in school, every description of how transistors work was pretty dry and had a lot of math involved. We suppose you might have had a great instructor who was able to explain things more intuitively, but that was luck of the draw and statistically unlikely. These days, there are so many great videos on the Internet that explain things that even if you know the subject matter, it is fun to watch and see some of the great animations. For example [Sabin] has this beautifully animated explanation of how MOSFETs work that you can see below.
It uses the same basic graphics and style as his earlier video on bipolar transistors (second video, below) which is a great one to watch, too. In all fairness to your electronics teacher, the kind of graphics in these videos would have cost a fortune to do back in the 20th century — just watch some of the videos we talk about in some of our historical posts.
Even if you are well versed in device physics, these videos are great if you want some help explaining electron and hole motion through semiconductors. One thing we were pleased to see is the smiley-faced electrons don’t frown when they are doped like on the bipolar transistor. We hate to think of our friendly electrons being unhappy.
In today’s world, you can get by without knowing how devices work. After all, a Raspberry Pi works great without knowing what’s happening at this level. Of course, you can drive a car without understanding the engine, but you can bet every driver at the Indy 500 knows exactly how the engine works.