So you wanna know what a crystal radio is eh. Well you came to the right place. About 3 years ago on my many google adventures I was searching and reading away about a very cool person named Tesla, long story short I ended up seeing a post about the crystal radio, so I clicked away and my imagination was captivated when I learned it was possible to create a radio that uses no batteries.
WHAT IS A CRYSTAL RADIO?
A crystal radio is a very simple AM radio receiver which requires no batteries to work. By using a long wire as an antenna it gathers enough of the radio signals from nearby transmitters to power a crystal diode. This special diode demodulates the signals and then plays them as sound through a ceramic earphone.(Check my blog for instructions how to build a custom earpiece which works great) The earliest use of this type of radio was to receive Morse code. Early radio used spark gap and arc transmitters but the downside was they were not able to detect weak signals.
A crystal radio has three main components:
**The antenna which the electric currents are induced by the incoming radio waves. The antenna converts the energy in the radio waves striking it to an alternating electric current in the antenna passing it to the tuning coil. The larger the antenna the more power it can collect.
**A tuned circuit ( resonant circuit) this allows to select the frequency of the radio station. The tuned circuit consists of a coil (inductor) as well as a capacitor. By connecting them together you create a circuit that resonates at the frequency of the desired station. The coil or capacitor is adjustable allowing you to tune to different frequencies.
Check out: How to build Crystal Radio
Hack a buzzer into a Crystal Radio earpiece
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