An iron ring, a copper wire and a magnetic needle: this was all the British scientist Michael Faraday needed to generate electricity from magnetism for the first time, more than 180 years ago. Today, the principles of electromagnetic induction are used in countless devices: steam engines, huge power plant generators—and bicycle dynamos. In the past, side-running dynamos were the most common, the heads of which were placed directly on the tire and buzzed loudly. Meanwhile, hub dynamos have taken over. They sit in the center of the front wheel and work much more efficiently. The main element of the hub dynamo is a coil made of an iron core and copper wire . A metal cage surrounds the coil . The hub of the front wheel , which is equipped with small magnets , rotates around this coil construction.
Every time the magnets move over the coil, they change the magnetic field above it, thus generating voltage and electric current. The metal cage works as an amplifier. At both ends of the coil, the alternating current is intercepted and transmitted through wires to the front and rear lights. Muscle power and knowledge illuminate our way. Michael Faraday would have been very proud.
How does it work?
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