After I joined the high-voltage-electronics-hobbyist community, I set out to build another Tesla coil on my own. Most designs use either spark gaps or solid-state circuits, however, spark gaps aren’t as efficient, solid-state can get quite complex, and the latter might require more expensive components unlikely to be found in my stash of scavenged parts. I like exploring how things worked, and I thought-if I understood the concepts behind the Tesla coil maybe I could create another option.
Tesla coils are resonant transformers driven by a “switch” that generates oscillations. Since coil designs are identified by these excitation mechanisms, it was clear that investigating different oscillators was the way forward. My curiosity was sparked when I found the Armstrong oscillator, used in tube radios. Its continuous, not pulsed, output distinguished it, and I realized I could implement this design in a Tesla coil with vacuum tubes-that’s where this vacuum-tube-based coil project began.
Unbeknown to me at the time, I actually wasn’t the first to explore this--others had experimented with continuous-wave and vacuum-tube-based circuits before. Still, I got to try developing an interesting design, working around constraints to add to a classic build. Plus, it generates lightning that I can touch, which is pretty cool.