: Hello, I am new to Tesla Coils and I am in process of designing one using a
: flyback transformer. I am curious whether I can have a duel resonance
: between the primary and secondary since the transformer is already wound
: and I have no control over the inductance. Also is it possible for it to
: look like the 'classical' tesla coil with a slender middle that goes to a
: toroid top load? Most of the designs that I have seen using a flyback only
: have small arcs from a pointed electrode.
The complex geometry of the secondary winding is not optimum for getting the sharply defined resonant frequency that's desirable for a Tesla Coil. Various sections of the secondary "Pi" winding will combine with various parasitic turn-to-turn capacitances to create various combinations of LC circuits inside the winding. So, instead of getting a single (and optimal) resonant frequency, you'll get a variety of suboptimal resonant frequencies. These separate resonant frequencies only excite subsections of the winding, but not the entire winding (as in a Tesla Coil).
Although you can tune the primary so that it is tuned to one of these suboptimal frequencies, the output will be disappointing when compared to a classic Tesla Coil. You also risk internal arcing as some sections of the winding can become overstressed. Once the winding insulation system fails, the winding is destroyed and must be rewound or the transformer replaced. Flybacks are good for low to moderate output power applications. There are many circuits on the Internet that will drive flybacks to deliver tens or even hundreds of watts of output power. You may wish to search the forum section on the 4hv site: <a href="http://www.4hv.org">http://www.4hv.org</a>
If you search for "flyback driver" on the 4hv site, you can also read numerous discussions about flyback transformers, driver circuits, and results obtained from a variety of experimenters. You may also wish to read the HV Wiki to read about Flyback Transformers:
Good luck and best wishes,