Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Re: Crystal Radio Questin

  1. Dec 22, 2008 #1
    I am new to this website but I would like to know how to build a homemade radio using an electro magnet and a germanium diode crystal. Are ther any other components required to complete the construction of the radio?
    Last edited: Dec 22, 2008
  2. jcsd
  3. Dec 22, 2008 #2


    User Avatar

    Staff: Mentor

    You will need a long wire as an antenna, and a couple other things. Sounds like this is what you need:


    Welcome to the PF!
  4. Dec 23, 2008 #3
    There starting point would be getting very sensisitve high impedance headphones which are not too common these days. Piezo ones might be the best?? Old fashioned crystal sets tended to use 2000 Ohm headphones which matched well to the output of the diode dertector.
  5. Dec 26, 2008 #4
    I built several crystal radios when I was young. I fell asleep many nights listening to the strongest local news station, WPEN. I thought it was great that it didn’t require batteries. I wound the coils myself around an empty toilet paper roll and would use 28 to 30 gauge wire. It only required a germanium diode (germanium because its forward voltage is only .25 volts compared to a silicon diode’s .65 volts), a capacitor (I used a "tuning gang"), and an earphone. By 4th grade (early to mid 1960’s), I was already building amplifiers with state of the art transistors (vacuum tubes were still the norm in radios and televisions at that time), so I’d connect my crystal set to the input of the amplifier I built to allow my brothers and I to listen to WPEN at night.

    Though analog radio is still with us, if or when they go “all digital”, it will make crystal radio sets obsolete. I find that a sad thought.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook