Practical Audio Electronics

16  |  Diodes

Diodes let current flow in one direction but not the other

In Chapter 3 diodes were introduced at a theoretical level, described in the context of the semiconductor materials from which they are fabricated. Here that introduction is expanded into a more practical examination of what diodes do and how to use them. The diode is the simplest of all semiconductor devices, made (usually) by sticking two pieces of semiconductor material together, one p-type and one n-type, in order to form a p-n junction.

A diode’s two terminals are referred to as the anode and the cathode, as shown in Figure 16.1. The fundamental action which characterises the behaviour of a diode is that it allows current to flow in one direction but not the other. ...