Electronics Cookbook

Chapter 5. Transistors and Integrated Circuits

5.0 Introduction

Transistors are used to control the flow of a current. In digital electronics this control takes the form of an on/off action, with the transistor acting as an electronic switch.

Transistors are also used in analog electronics where they can be used to amplify signals in a linear manner. However, these days, a better (cheaper and more reliable) way to do this is to use an integrated circuit (chip) that combines lots of transistors and other components into a single convenient package.

This chapter does not cover all types of transistors or semiconductor devices, but instead focuses on the most common ones, which are generally low in cost and easy to use. There are other exotic devices like the unijunction transistors and SCRs (silicon-controlled rectifiers) that used to be popular, but are now seldom used.

The other thing deliberately left out of this cookbook is the usual theory of how semiconductors like diodes and transistors work. If you are interested in the physics of electronics, there are many books and useful resources on semiconductor theory, but just to make use of transistors, you do not really need to know about holes, electrons, and doping N and P regions.

This chapter will concentrate on the use of transistors in their digital role. You will find information on using transistors for analog circuits in Chapter 16.

In this chapter, you will encounter a wide variety of transistors. Appendix A includes ...