If you want to control it from a 3.3 V MCU that can’t handle the high-side voltage on its pins, you can add a NPN transistor section as shown – this inverts the logic, making it into a more ...

and Field Effect Transistors (FETs). BJTs are controlled by current, while FETs are controlled by voltage. Within these categories, there are further subdivisions such as NPN and PNP BJTs and ...

William Shockley improved on this design with his junction transistor, a three-layer sandwich of different types of semiconductor. The diagram illustrates the basic design of an NPN junction ...

The first transistor was about half an inch high. That's mammoth by today's standards, when 7 million transistors can fit on a single computer chip. It was nevertheless an amazing piece of technology.