Building a Crystal Radio
In This Chapter
Understanding how crystal radios work
Building your own crystal radio
Listening to stations on your radio
In this chapter, we guide you step by step through how to build one of the simplest of all useful electronic circuits: a crystal radio. On this radio receiver you can pick up AM broadcasts.
Now, this radio is pretty basic: it isn’t a particularly good receiver, only one person can listen to it at a time (it uses an earphone instead of a speaker) and its tuning isn’t very sensitive. You’re lucky if you can receive two or three different stations even if dozens are broadcasting in your area. But this crystal radio is unique in that, unlike every other electronic circuit we describe in this book, it has no obvious source of power: no batteries or other power supply. The only source of power a crystal radio uses is from the radio waves themselves.