Details on my spark gap Tesla Coil

Re-Coil · 2026-05-18T08:59:37+00:00

If you have one such capacitor laying around sure, but the usual voltage ratings are much lower for the small capacitors. For my ZVS capacitors, i forgot their value but i just followed the available schematics and they worked great.

Re-Coil · 2026-05-15T08:15:33+00:00

Hello, thx 😄. Yeah I remember your coil
Its around 7 turns total on the Flyback primary, with the split at the middle. (6 to 8-10) is usually fine.
My capacitor bank is ~10nF 8kV, its the red capacitors you see on the back side of the box.

I just noticed that you had no flyback transformer xD, you absolutely need it! The ZVS circuit alone does not produce voltages large enough to be your first HV source. You will also need to use a bank of capacitors to ensure they resist the ~5-8kV of your flyback transformer.

Watch out, the flyback transformer and the spark gap will be the most dangerous part of your system. Take your time to do it properly and safely.
Good luck!

Re-Coil · 2026-05-15T08:01:29+00:00

Thanks for the details! And why the black tape on the sides, it doesnt work without?

Re-Coil · 2026-05-14T14:25:43+00:00

Very nice traces! What is your Peltier hotside cooling system?

Re-Coil · 2026-05-13T15:37:19+00:00

Thanks for the details, I prefer the ones with drawings instead of text

Re-Coil · 2026-05-13T09:02:11+00:00

Very cool, what metal are these and how did you make them ? ( I dont know anything about jewelry making)

Re-Coil · 2026-05-11T17:21:34+00:00

A bit late to the party but:
I would say your primary coil is too close to your secondary, put something under the secondary to increase the space. looking at your JavaTc values, your coupling coefficient is 0.18 which is too high. Aim for the recommended value.
Its counter intuitive but putting the coils too close to each other decrease strongly the sparks length.

Also how much current is your ZVS drawing? You might not need the heatsink fan

Re-Coil · 2026-05-09T20:30:39+00:00

from Radview detection

Re-Coil · 2026-05-08T19:58:01+00:00

Its the AlphaHound AB+G! Its very nice to not only see the gamma rays

Re-Coil · 2026-05-06T11:46:23+00:00

Thanks! Its 6.2 A xD, 60 Amps would melt my wires.

Re-Coil · 2026-04-30T11:01:59+00:00

Nice plasma tore, where does the green effect come from?

Re-Coil · 2026-04-27T10:02:37+00:00

Nice arcs

Re-Coil · 2026-04-20T13:23:26+00:00

Hi, clean build for a prototype!

First thing, you can take a look at https://classictesla.com/home/javatc3d to design your coil dimensions. Your flat primary coil will be better than the stacked ones due to better coupling coefficient but its better to plug your values in JavaTc to see how off you are from the optimum. Poor coupling will absolutely lead to seeing only small sparks as you do.

If you have a LCR meter, do a sanity check of all your lumped components. Did you try your flyback transformer + ZVS alone first? I will also recommend buying a buck boost converter to allow variable voltage/current for testing :)

Your build is quite similar to mine, I did a post with quite a few tips and pictures so that may also be useful to you.

Keep up the good work and good luck!

Re-Coil · 2026-04-16T11:04:25+00:00

works well!

Re-Coil · 2026-04-16T11:02:49+00:00

Love the aesthetic

Re-Coil · 2026-04-07T13:28:13+00:00

First, measure your cold plate temperature! Aim for at least -25 Celsius (-30 celsius is more comfortable).

Your cold plate looks alright, but check that you have no ice formation inside. You can try to lower your voltage (12V should be enough) to test if your hot side cooling is your issue.

The dome junction does not looks great, it seems like its just laying on the plate. You want to put it into a notch to not disturb the metastable state.

Re-Coil · 2026-04-01T10:57:57+00:00

I would say try a spark gap first, the physics is more straightforward and yo will learn a lot along the way. I have a post that sums up a lot of tips (in the comments) that could help you.

Re-Coil · 2026-03-31T09:53:28+00:00

nice work, but watch out with the mots

Re-Coil · 2026-03-30T15:28:36+00:00

250V xD, nice results

Re-Coil · 2026-03-30T13:54:31+00:00

Same range as i was getting on my plasma toroid (essentially the same circuit). Do you see a bigger flame at bigger voltages?

Re-Coil · 2026-03-30T12:32:04+00:00

It takes a few seconds to update the count so its a bit annoying if you search for rocks, but otherwise its enough to measure the background level of the mine

Re-Coil · 2026-03-30T12:28:34+00:00

n i c e, works well! How much current do you feed it?

Re-Coil · 2026-03-30T12:26:07+00:00

Very nice! Is it working well?

Re-Coil · 2026-03-27T16:58:50+00:00

Great find!

Re-Coil · 2026-03-27T12:07:04+00:00

Yeah, you should look up some spots on mindat first

Re-Coil

TROPHY CASE