This circuit was found in a 1999 English magazine, but can be easily assembled with BC548 transistors or any general purpose NPN. The circuit works with the energy generated by a small DC motor that acts as a dynamo. The energy charges a capacitor and powers the radio. L1 consists of 100 turns of wire 28 in a ferrite rod and CV is a variable obtained from an unused AM radio. This project is interesting to demonstrate the functioning of energy sources, such as dynamo. The crystal headset can be a piezoelectric ceramic capsule.
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