We all know, at least intellectually, that our computers are all built with lots of tiny transistors. But beyond that it’s a little hard to describe. They’re printed on a silicon wafer … ...

Later, I helped a friend disassemble a Tesla model, and the mass of circuit boards inside was overwhelming—until I drew 5 diagrams that clarified how the motor controller works. Honestly, even friends ...

The classic transistor amplifier circuit then has a pair of resistors in series between supply and ground, forming a potential divider that gives the base its bias.