# Vacuum Tube Tesla Coil

#### T3$l@ Joined Aug 1, 2014 6 Hey guys! I'm kinda a n00b as far as circuitry goes, but am trying my hand at making a vacuum tube tesla coil, based on the tutorial at:http://www.instructables.com/id/How-To-Build-A-Vacuum-Tube-Tesla-Coil-VTTC/?ALLSTEPS. The circuit diagram for the project is http://www.stevehv.4hv.org/VTTC1/dual811Aschematic.JPG, with a few modifications. I need help figuring out a couple of things: 1. Do I use the entire 100ft and 1000ft of wire respectively for the primary and the secondary coils? 2. How do I connect the components? Regular home wiring with rubber sheath? 3. Where do I connect what as far as the transformers go (which one to electric plug, which one to coil etc.)? 4. What can I make the toroid of? 4. If my secondary coil is 11in. high and around a 2in. wide pipe, what changes do I need to make? 5. What terminals of the vacuum tube triode do I connect where? 6. What is in parallel with R1 in the diagram, just before series connection to the triodes? Thanks in advance, and pardon my ignorance. #### alfacliff Joined Dec 13, 2013 2,449 the coils around the resistors marked r1 are to supress vhf parasitic oscilations. no you dont use the entire spools of wire, use only as much as the instructions tell you to. house wireing can be used if you keep the wires away from ground, there is high voltage in there! the toroid is aluminum, it is a corona hat, also used to add capacitance to the top of the coil. 4. might have to adjust the number of turns in the coil connected to the plates of the tubes. the toroid should be as smooth as possable, any roughntss will cause corona voltage loss to occur. put a tack on top and watch the sparks come off into the air. #### BeerBelly Joined Dec 16, 2013 29 Just some things to be aware of. This is a radio transmitter. Any changes you make will effect the tuned circuit. Also these will cause plenty of interference on their osc. frequency and odd harmonics. Thread Starter #### T3$l@

Joined Aug 1, 2014
6
the coils around the resistors marked r1 are to supress vhf parasitic oscilations.
no you dont use the entire spools of wire, use only as much as the instructions tell you to.
house wireing can be used if you keep the wires away from ground, there is high voltage in there!
the toroid is aluminum, it is a corona hat, also used to add capacitance to the top of the coil.
4. might have to adjust the number of turns in the coil connected to the plates of the tubes.
the toroid should be as smooth as possable, any roughntss will cause corona voltage loss to occur. put a tack on top and watch the sparks come off into the air.
Could you tell me what sort of changes in number of turns and all, @alfacliff

#### alfacliff

Joined Dec 13, 2013
2,449
since your coil is shorter, there would be less turns, that gives less inductance and the primary ( plate resonant circuit ) would have to be a few turns smaller to resonate on the same frequency.

#### T3$l@ Joined Aug 1, 2014 6 since your coil is shorter, there would be less turns, that gives less inductance and the primary ( plate resonant circuit ) would have to be a few turns smaller to resonate on the same frequency. Okay. @alfacliff, can you help me calculate primary turns if secondary has about ~600 turns? Thanks. #### DerStrom8 Joined Feb 20, 2011 2,373 Hi T3$l@,

I have built several Tesla coils before, and am currently working on a DRSSTC. I've learned it's never good to start off with a solid state type, especially if you aren't very familiar with circuitry. I would really recommend you start with a small spark gap style one, because it'll give you a better understanding of how they work. Then you would understand how a solid state/vacuum tube Tesla coil would need to function.

Steve Ward is a pioneer in the area of Solid State Tesla Coils, and it is his design you're using. Notice he tells you exactly how many turns of wire to use for each coil, so I'm not sure what your question is all about. The information is there.

If I am understanding you correctly, you're trying to build a Tesla coil that's on Instructables, but you're using a different circuit from Steve Ward. I really recommend you work with one or the other, and don't mix-and-match until you actually know how it all works.

Really, the best advice I can give you (and this is from experience) is to do more research before continuing the build. I know it's hard to not jump right in, but it is definitely worth it. Research how a Tesla coil operates, the theories behind it, and then read up more on various VTTC designs on the web. Then you can get a general idea of what is needed to make them work and how they work, and it will be easier to build one of your own. Tesla coils are not a very good project to simply build on a whim--you need to do a lot of planning before you can do much with them.

That being said, I look forward to seeing your progress. Tesla coils are a lot of fun to build, and I hope you can get one working soon. But just remember that they are not for beginners. You should learn more about electronics before even attempting to build one.

Regards,
Matt

#### T3$l@ Joined Aug 1, 2014 6 Dear Mr. DerStrom8Am I incorrect in understanding that a VTTC is different than a Solid State? From all I researched, it seemed so, which is why I decided to do this one. The confusion about the designs arose thus: I was making it and getting stuff according to the Instructable, when I realised the guy was doing things differently than Mr. Ward's schematic. Maybe it was an error but I got confused. Right now, the major points of confusion due to these two places clashing are- 1. Should I follow the Instructable (where the Secondary Former is 12 inches, 2 inch diameter) and wire length is 1000ft., or do I follow Mr. Ward, buy a bigger former and make it 14 inches with diameter 2.3"? 2. Can I get rid of the inductance coil (14 turns 14 AWG) middle of the schematic? 3. For the primary, should I make it according to Mr. Ward, or using the Secondaryrimary ratio, change using my secondary's specs? The no. of turns in Mr. Ward's design is 1111:22 (~50:1), and thus make my coils in ratio 800:16? 4. What changes can I make to adapt this to 240V power? I have researched quite a bit, but please do tell more places. Thanks a lot for your great answer, hope to get more advice. #### DerStrom8 Joined Feb 20, 2011 2,373 Dear Mr. DerStrom8Am I incorrect in understanding that a VTTC is different than a Solid State? From all I researched, it seemed so, which is why I decided to do this one. You know, I'm not sure if vacuum tubes are considered solid-state devices or not. I just mean "solid state" as in no moving parts and no spark gap. There are many different designs for solid state Tesla coils, including the ISSTC (Interrupted Solid State Tesla Coil), the DRSSTC (Double-Resonant Solid State Tesla Coil), the QCWDRSSTC (Quasi-Continuous-Wave Double-Resonant Solid State Tesla Coil), and the OLTC (Off-Line Tesla Coil). I guess technically Valves don't count as Solid State, but my point still stands--it's usually best to start with SGTCs. The confusion about the designs arose thus: I was making it and getting stuff according to the Instructable, when I realised the guy was doing things differently than Mr. Ward's schematic. Maybe it was an error but I got confused. Right now, the major points of confusion due to these two places clashing are- 1. Should I follow the Instructable (where the Secondary Former is 12 inches, 2 inch diameter) and wire length is 1000ft., or do I follow Mr. Ward, buy a bigger former and make it 14 inches with diameter 2.3"? 2. Can I get rid of the inductance coil (14 turns 14 AWG) middle of the schematic? 3. For the primary, should I make it according to Mr. Ward, or using the Secondaryrimary ratio, change using my secondary's specs? The no. of turns in Mr. Ward's design is 1111:22 (~50:1), and thus make my coils in ratio 800:16? 4. What changes can I make to adapt this to 240V power? I have researched quite a bit, but please do tell more places. Thanks a lot for your great answer, hope to get more advice. You know what, You may find 4hv.org very useful. I want to say Steve Ward is the owner, and it has a forums section with some very helpful members and moderators. I have received help from them before for my TC builds, and I think they have a lot to offer you. In general, I have learned not to follow many Instructables regarding electronics. Some of them are ok, but I would not choose them over more well-known experts. I strongly recommend working using Steve's designs whenever possible. Receiving help from him and the others at 4hv would be very beneficial. You can also do a search there for a vacuum tube tesla coil and it'll turn up quite a few threads. As for other links and documentation, you may like to read Steve Ward's page on VTTCs: http://www.stevehv.4hv.org/VTTCfaq.htm Good luck! Matt Thread Starter #### T3$l@

Joined Aug 1, 2014
6
Dear everyone
I have resolved a lot of the errors. Now, I just need help figuring out if it's okay removing the inductor coil in the middle (across R1, says 14 turns 14 awg).

Also, I need help understanding where to connect what on the vacuum tubes, photos linked.

http://snk.to/f-ct3l6nc7

http://snk.to/f-cdzc8vbe

Thanks.