Topic 22. Transistors
There are several classes of transistor. The class that is described in this Topic is known as a silicon npn transistor. It is also known as a bipolar junction transistor, or BJT.
The BJT class of transistor described in this Topic was the first to be widely used. Another important class is the MOSFET, described in Topic 26. We shall not go into the reasons for these names, and you need not remember them, except for ‘BJT’ and ‘MOSFET’.