What Is a Tesla Generator?

A Tesla generator spins magnets past windings of copper wire, which induces a magnetic current. This current can be used to produce electrical voltage, which can be used to do work - anything from lighting up a lightbulb, to charging a cellphone, to charging a battery. The spinning magnets are called the rotor. The set of mounted wire windings, which are held stationary above the rotor, are call the stator. The rotor magnets and stator windings never touch each other, but they are held in close proximity in order to get the strongest results. The path of the spinning magnets should be at right angles with the wires of the coils, passing right below their center, in order to induce the most current. Here is an image of an alternating current generator similar to the one I've built:

 

 Image Credit: http://jnaudin.free.fr/images/mromag3.gif 

In a micro-hydro generator like this one, running water is used to spin the rotor. The generator transforms mechanical energy, which is the physical spinning of the rotor, into electrical energy. The electrical energy, which begins as alternating current, runs through copper wires into a series of diodes, which rectify the current. Rectification of alternating current turns it into direct current, which the item being powered, called the "load," is then able to use. This is needed because alternating current reverses direction periodically, and the load uses current that only flows in one direction. Here is a diagram of a diode rectifier: 

 

Image Credit: http://www.radio-electronics.com/info/circuits/diode-rectifier/diode-rectifier-full-wave-bridge-01.gif 

Anything that spins the rotor can be used to generate electricity by this method. You could use compressed air to spin this rotor, or, if the rotor was connected to a handle and crank, the energy of your own arm.

The principles may seem complex at first, but a generator like this one is inexpensive to build. The parts needed can be found at a hardware store and an electronics store. If you already have a drill, a dremel, an old CD case and some CDs you don't mind repurposing, the rest of the materials cost about $30.00.

What Materials Do I Need To Build a Tesla Generator? 

Image by Steven Jackson

• 9 Compact Discs
• One Spindle-Type Compact Disc Case, 3" high
• One 9" Plastic Platter
• One-Pound Spool of Enameled 24 AWG Magnet Wire
• Six ½ inch x 1/8 inch Neodymium Rare Earth Magnets
• Two Bridge Rectifiers
• One Capacitor Rated at 200 Volts and 470 microfarads
• One Electronics Breadboard
• Ten 1/8" Nylon Spacers
• One Plastic Ice Cream Scoop
• One Brass Bolt with Nut
• One Hose
• One Hose Clamp
• Four Pop Rivets
• Two 2" Diameter Wooden Discs
• One 1" Bolt with Nut 
• One 1/2" Nylon Spacer 
• One Small Water Pump (Optional)
• One Large Rechargeable Battery (Optional)
• One 5-Gallon Bucket (Optional)

These are the tools and adhesives I needed:

• One Tube E6000 Glue
• One Roll Clear Tape
• Dremel With 1/16" and 1/8" Drill Bits and Router Bit
• Dremel Router Table 
• Dremel Vise 
• Power Drill with Stepper Drill Bit
• Digital Multimeter
• Two C-Clamps
• One Piece Rough Sandpaper
• One Sharpie
• One Philips Screw Driver
• One Crescent Wrench 
• One Soldering Iron with Lead Solder
• Belt Sander (Optional) 
• Oscilloscope (Optional)