an overlapping condition of current waves during consecutive passes springs 16 are preferably formed of stainless steel and have enough resiliency to prevent u201c bottoming u201d of magnet 12 stainless steel should be used because of its antimagnetic property springs 16 are not absolutely required for operation but they do assist in conservation of energy by rebounding magnet 12 wire coil 18 is formed of insulated copper magnet wire the preferred wire gauge is awg 30 wire coil 18 is optimized for the desired application by carefully selecting the wire gauge and coil geometry altering the wire gauge changes the voltage generated by the wire coil as the wire is made smaller the voltage increases resulting in a reduction in current with regard to the geometry of wire coil 18 the inside portion of wire coil 18 must be as close to magnet 12 as possible meaning that the thickness of the barrel wall at spool 34 must be very thin around 0 05 inches to keep the coil in the highest magnetic density region of the magnetic field the diameter of barrel 14 is about 0 88 inches the outside portion of wire coil 18 is limited by the strength of magnet 12 and the bore of barrel 14 because magnetic field strength drops off rapidly as distance from the magnet increases the length of coil 18.