Dynamos are brilliantly simple direct-current generators that are used all over the world. While popular today, the basic design was established nearly 200 years ago, placing them among the most important inventions of the 19th century.  The first true dynamo was built in 1832 by a French instrument maker, Hippolyte Pixii, who based his design on the principles of Michael Faraday (one of our favorite magnetic personalities!).  Direct Current To be fair, Faraday actually built a similar device in 1831, but it lacked one critical component necessary to a true dynamo –– the commutator. Pixii’s commutator converted the alternating current generated by Faraday’s design into direct current. This updated invention revolutionized industries, allowing companies to power their machines. In fact, its basic design has proven so useful that it’s still employed today in hundreds of applications, although some necessary improvements have been made along the way. For example, early dynamos generated electricity in shorter spurts –– a problem for certain machinery.   How Dynamos Work To understand how dynamos work, let’s examine one through the lens of a familiar application –– battery-free lights on bicycles. These bike lights enable riders to light up the road in front of them by simply pedaling. Dynamos come into play by using the energy created through the bike’s movement and turning it into electricity.  Eddy Current How is this possible? Well, it all starts with something called an eddy current –– a swirling magnetic current created when the magnetic field surrounding a stationary conductor varies. For reference, a famous eddy current experiment involved a magnet being dropped through a copper pipe. The eddy current inside the pipe reduced the gravitational pull, causing the magnet to fall slower than normal.   Let’s go back to the bike example to see how an eddy field is created: Dynamos contain magnets, and they’re often placed near the axle fork, next to the wheel rim. When the wheel turns, it acts against the magnets inside the dynamo, causing them to spin as well.  The magnets are surrounded by a spool of copper wire, and when the magnets spin, they excite the electrons inside the copper wire. The stronger the magnet and the faster it turns, the more it excites the copper electrons. This excitement creates electricity, which is then passed through the wires.  Before reaching the light, the electricity travels through a capacitor. Doing so stores some of the electricity, which allows the light to stay lit even if the rider comes to a halt and the eddy current wears off. Of course, if the rider stays stationary for a long period, the light will eventually go out. How Apex Magnets Can Help If you need smaller, powerful magnets for your next project, you can trust Apex. With a wide variety of industrial-strength magnets, you’ll find exactly what you need. Contact us for any additional product information or for help nailing for the parameters of your next magnetic project.