Complete Electronics Self-Teaching Guide with Projects

Chapter 3

Introduction to the Transistor

The transistor is undoubtedly the most important modern electronic component because it has enabled great and profound changes in electronics and in your daily lives since its discovery in 1948.

This chapter introduces the transistor as an electronic component that acts similarly to a simple mechanical switch, and it is actually used as a switch in many modern electronic devices. A transistor can be made to conduct or not conduct an electric current—exactly what a mechanical switch does.

Most transistors used in electronic circuits are bipolar junction transistors (BJTs), commonly referred to as bipolar transistors junction field effect transistors (JFETs) or metal oxide silicon field effect transistors (MOSFETs). This chapter (along with Chapter 4, “The Transistor Switch,” and Chapter 8, “Transistor Amplifiers”) illustrates how BJTs and JFETs function and how they are used in electronic circuits. Because JFETs and MOSFETs function in similar fashion, MOSFETs are not covered here.

Projects in this chapter can help you to build a simple one-transistor circuit. You can easily set up this circuit on a home workbench. You should take the time to obtain the few components required, and actually build and operate the circuit.

In Chapter 4, you continue to study transistor circuits and the operation of the transistor as a switch. In Chapter 8, you learn how a transistor can be made to operate as an amplifier. In this mode, the transistor produces ...