This PWM driver board is the cheapest I have seen. You couldn't buy the parts and make it yourself for the cost of the kit. $14.99 Capable of 20 amps output up to 15V.
http://ww.electronic-light.com/advan.html
I talked to the seller and he was gracious to even provide me with the schematic so we could work out the proper changes needed.
I am not failure with this 555 configuration, as it doesn't even use the normal output. I will have it up and running on a simulator later today.
Likely, R3 will need to be reduced to a minimum for stability, and a 1 meg pot add inbetween it, and Q1.
The 555 produces a triangle wave that is then compared for the central balance, where the pot R6 sets the balance point for square wave duration. The comparator outputs a square wave. It will be very simple to add a pot (and cap if needed) to very the frequency.
One setback is that it uses a diode D1 to absorb the "kickback" and it is this "kickback" that does the work in a Meyer-Dingle system. I am presently posting some circuit experiments that can teach anybody what is happening.
I do not personally have this circuit board, and won't be buying one, as I make my own boards and circuits. This is just for people who don't , and are looking for a cheap way to go.
I have been working on circuits that can reflect this energy back into the output circuit, instead of waste it defeating the dipole, while protecting the mosfet from blowing.
It's also very possible to gang two or three of these together with a separate controller, for intended desired results.
Look for Discovery Circuits in this form thread.
Thomas
