Electronics Projects: How to Assemble the Crystal Radio Circuit - dummies

Electronics Projects: How to Assemble the Crystal Radio Circuit

By Doug Lowe

Before you embark on assembling the various electronic parts of a crystal radio, you will need a base and a few other parts. Here’s a list of the parts you’ll need to assemble the circuit:

  • The base, wood, about 6 by 9″, painted or stained (so it looks good when you are done)

  • The coil

  • A four-position barrier strip

  • A germanium diode (1N34A or similar)

  • A tuning capacitor (optional)

  • One length of hook-up wire, approximately 1.5″ long

  • Two lengths of hook-up wire, approximately 3″ long

You’ll need the following tools to build the crystal radio circuit:

  • A hot glue gun and some glue sticks

  • A Phillips-head screwdriver

  • Wire cutters

  • Wire strippers

  • Soldering iron and some solder


The individual terminals of the barrier strip are numbered from left to right, 1 through 4. Terminal connectors in the top row are given the letter A, and those in the bottom row are given the letter B. Thus, the terminal at the top left of the barrier strip is terminal 1A, and the terminal at the bottom right is 4B.

To assemble the crystal radio circuit, follow these steps:

  1. Glue the barrier strip, tuning capacitor, and coil to the board.

    Be sure to give the glue enough time to cool and harden before you continue.

  2. Connect the diode between terminals 1A and 3A.

    Interestingly enough, the direction in which you connect the diode doesn’t matter in a crystal radio circuit.

  3. Strip about 3/8″ of insulation from both ends of all three lengths of hook-up wire.

  4. Connect one end of the 1.5″ length of hook-up wire to terminal 2A on the barrier strip, and then connect the other end to terminal 4A.

  5. Use some sandpaper to gently scrape the enamel insulation off the ends of the wire.

  6. Connect the two wires from the coil to terminals 1A and 4A.

  7. Solder one end of one of the 3″ hook-up wires to the center lead of the capacitor and one end of the other 3″ wire to either one of the other leads.

    It doesn’t matter which of the two outside leads you use.

  8. Connect the free ends of the wires you soldered in Step 7 to terminals 1A and 1D of the barrier strip.

    You’re done!

When the radio circuit is assembled, look it over to make sure all the pieces are connected correctly.