Electronics Projects: Materials for a Crystal Radio Circuit
A crystal radio is a good project to hone your electronics skills. You’ll need a handful of parts to build your crystal radio. The following is a recommended list:
At least 50 feet of antenna wire. You can use almost any wire for the antenna. A good option is 18-gauge solid hook-up wire, which you can buy at RadioShack.
A few feet of hook-up wire to connect the radio to a ground connection.
At least 50 feet of 30-gauge, enamel-coated magnet wire. You can buy this at RadioShack.
Something to wrap the coil on. An empty soda bottle works just fine.
A variable capacitor, also called a tuning capacitor. These are getting hard to get, as RadioShack no longer carries them. However, you can easily harvest one out of an old radio that doesn’t work, or you can purchase them online.
Note that the variable capacitor is an optional component. If you can’t find one, you can still build your crystal set without one; you just won’t be able to tune out competing stations.
A germanium diode. You can’t buy these at RadioShack, but you can order them over the Internet. Just use your favorite search engine to search for 1N34A, and you’ll find several suppliers.
A piezoelectric earphone. Regular earphones like the kind used with an iPod or cell phone won’t work. Search for piezoelectric earphone and you’ll find several suppliers that sell them for about $3.
A board to mount the radio on. About 6 by 9″ should be sufficient.
Something to make your electrical connections. A four-pole barrier strip from RadioShack (part number 274-658) works well.
If you have an old radio that doesn’t work lying around, feel free to open it up and harvest its parts. In particular, look for the tuning capacitor. You’ll be able to spot it easily because it will be connected to the radio’s tuning knob.
The germanium diode, tuning capacitor, and piezoelectric earphone are the three parts that are a bit difficult to find. You may want to purchase a crystal radio kit from a hobby or school-supply store and harvest those three parts from the kit.