I have built a small, simple linear generator. It works, but I'm sure it could be more efficient because I didn't know how many windings of magnet wire to use. I know there is a formula I could use to determine how many windings but have been unable to find it. Can someone provide me the formula or where I can find it?

Now for more details of the project in case that somehow helps. I have a cylinder about 2.5 cm long and about .4 cm inner diameter. I have a cylindrical neodymium magnet that just fits inside and is about .2 in height. Of course, when I hold my fingers at the ends and shake back and forth I get a small current. I would like to be able to light an LED (hopefully a super bright). I realize it will strobe on and off - which is exactly what I want. I haven't yet used it with an LED, but did connect it up to a multitester to see that I was generating a current. Perhaps I will need to upsize the magnet/change the cylinder size (diameter or length). I'm hoping I will not need to change things too much as I have space limitations. But I could change things a bit if needed. If anyone has thoughts, I would be happy to hear them, although the winding issue is more what I'm hoping to have answered.


  • $\begingroup$ Outer diameter of cylinder and cylinder material? $\endgroup$ Sep 16 '19 at 22:52
  • $\begingroup$ .5 outer diameter. Plastic material. $\endgroup$
    – toms0101
    Sep 30 '19 at 22:26

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