Check out this cool site concerning electrostatic generators.
One way is to attach some conductive spheres to a rotor. If you had 12 spheres on a rotor and the rotor was spinning at 720 r.p.m.this would give you 12 Hz. Once you have this setup you can use a communicatorelectrode to charge the spheres from your power supply and an output communicatorelectrode which would be the 12 Hz pulsed direct current. The powersupply could be any of the direct current ones found at the web site quotedabove. If you need the output to be 12 Hz alternating current, thenjust have two rotors connected to the same axis, one charge positive andthe other negative. Use the same 720 r.p.m. but have only 6 sphereson each rotor and diametrically aligned. In this case you would havetwo output communicator electrodes and both would be connected two eachother. The reason for using spherical conductors is a very importantpoint to remember whenever designing anything that will use high voltage. That is, never use a conductor that is not smoothly shaped. You don'tnecessarily need to use spheres, you could use aluminum soda cans for example. The higher the voltage you're dealing with, the more likely the electronswant to crowd together and fly off any conductors which have irregularitiesin the surface areas. Using the above methods you can inexpensivelycontrol very high voltages or static electricity as you like to call it. There are solid state methods for doing the above yet these methods getvery expensive as the voltage you're controlling goes up. This isespecially true if you're planning to produce alternating current waveforms.
All the best,
I'm needing to produce static electricity at 12 Hertz. What is the bestpossible means for producing this?