Dear All, I am very interested in working out the details of a triode or tube TC, because I want to compare this method to the newer solid state coil schematics. Can someone give me a pointer as to where I can find a basic concept, basic schematic, or layout, for a triode driven interruptor circuit that replaces the traditional spark gap? Sincerely, Miles
Miles, Tube Tesla coils as traditionally built do not use the tube as a replacement for the traditional spark gap. Instead the design is actually a power oscillator coupled to a secondary coil. They run in continuous wave fashion except they usually run on raw 60Hz AC. The continuous wave operation makes them much less "efficient" at producing long sparks for a given input power compared withspark gap coils. I usually include an interrupter circuit which permits a selectable number of AC cycles to be skipped. This gives the coil a pulsed or "staccato" type behaviour. This provides for interesting visual and sound effects in a sense. It also increases the "efficiency" in a way. Using this staccato pulsing method, the tube can be run harder when it *is* on. This results in longer sparks from a given tube. I show some of my work at my website at: http://hometown.aol.com/futuret/page3.html I'm not sure what schematics I have at my website. I had sent some information to Steve Ward in the past and he may still have some of this at his website, along with his own subsequent tube coil work. Richard Hull of Richmond VA once built a tube coil which used a hydrogen thyratron to replace the spark gap. Unfortunately this provided only for a one-way flow of current. Thus he was forced to terminate conduction at the first beat which prevented a complete transfer of energy and greatly hurt the efficiency of the system. He probably could have added a diode across the thyratron to conduct the reverse current. He considered using dual cross-parallel thyratrons but never got around to trying it.John