I have seen a lot zvs circuits around. But it looks like everybody uses switched power supplies for it. Not sure why. Some months ago I tried to run one from a non regulated power supply but it just destroyed itself. I think the load voltage drop may had caused it to fail...? Currently I'm using a computer PSU. But before I blow 2 more mosfets. Do you think it would work with a rectified transformer and a biiiigggg capacitor? I think I have 140 or 200k uF around.

I have seen people driving them with car batteries and even cell phone batteries for small zvs. I think "slow" voltage drop is not the problem. But sudden drop and drop below gate voltage.

My grandpa had this clock while he was alive. It was hanging here on the wall for years, not working. First I thought, I will find a store to rebuilt this clock. Then I just took it from the wall and discovered it had very little problems actually. The clock "hands" or needles were a bit bent and loose. One washer was a bit damaged too. Now it works. :-D

... not freezing anymore.

Ok I kinda gave up on the home made capacitors, they are not working.

Found some 630V and 1600V capacitors on a store. I could use 14 0.1 uF 1600V capacitors in series, and 7 strings in parallel. Or I could use 44 2.2uF 630 on a single string. Both would give around 50nF. But one layout is just a big series connection, which sounds a bit bad to me, and the other has parallel connections too. Price would be around the same on both cases.

These caps are not those meant for high pulse, but for 2 seconds I think they could work without exploding.

I made two of these in the hope they will work good for my Tc since I can't find cornell dubilier around here. Each one used to be 215-220nF. But then that was too high for my transformer. So I "unrolled" them a bit. Now each one is around 104nF. Which in series, doubles the voltage rating and gives me 52nF, close to the 50.1nF I need. Are these good for Tesla Coil? I also dipped them in electric motor varnish.

... Which I managed to burn and had to rewind.

All started with this old NST I found at a junkyard. Soon I discovered it was full of solid tar. After a lot of time melting it, thinking I was going to find an amazing iron core, I just found a very small core.



Square core, very common, nothing special. I don't even found what limits current in this thing. Like a magnetic shunt made of the same steel, across the middle of the core. Maybe this one didn't had one. They are so fragile, because they don't have any paper between layers, nor oil. And that tar just protects the case from hv, not the winding itself.



So I bought 2 C cores, did some calculations using a sofware and tested the primary number of turns. It worked.



I made the "official" primary by hand, just 134 turns. But the secondary was 15076 turns. Now imagine you winding 12 Tesla Coil secondaries... Then I made a improvised machine to turn the spool for me.



Looks ugly, works good.



The metal case.







Then I burn it when one day I decided to turn it on without any spark gap at the output. Reconstruction pictures.





Finishing is still rough, I'm not good with painting stuff.



Added oil.



And here a video of it before I destroyed it. Now it works just the same, but I don't have any new video. It is in portuguese, if you want to just see the sparks, go to 0:50.

Hi, not sure if this is the place to post this, but the hv section only has transformer and multipliers related topics.

I found this high voltage probe on a magazine called Silicon Chip. Here is the original project.
http://archive.siliconchip.com.au/cms/A_111937/article.html

And I can say that....... it doesn't work. Well the suggested resistance is way too high, 800Mohm. Just to show an example, if I blow some air into the probe it would read almost twice the voltage it was reading before. So I just looked for some technical specifications on a commercial probe available around here, it says 100Mohm resistance. Then I bought some 2 watts resistors, 60 of them, 1Mohm each and made the probe. Of course I ended with only 60Mohm, but for my voltage levels, that is enough and gives me more precision.

By the way, these things are supposed to be used with the ground side grounded before touching the hv with the probe. Since a lot of people would measure transformers, which don't have a grounded secondary, just forget about holding that thing on your hands. It could be very dangerous. I just connect both sides to the secondary and leave it far and alone.

Sorry for all the dirty around, I was working on a unfinished workshop.

Resistors around a brown pvc pipe, goes inside the white pipe. The hv tip ia a P10 plug with a copper wire soldered inside. Some silica gel to avoid moisture inside. And the wires that go to ground and to the multimeter. Also a trimpot and other resistors to calibrate the voltage divider.



The most important thing to avoid external interference due to the high resistance. Dip all in resin. I used fiberglass resin.



Some simple voltage doubler setup to calibrate it.



Left side is voltage from doubler, right side is milivolts after the probe.



Done. "Probe 1000:1".

Hi all. I will post the same text I just posted on facebook. I'm still having connection problems...

I built a hv transformer, pole style, no current limiting inside, I use an external ballast. First time I tried to turn it on without a spark gap on the insulators, it just fried the secondary. Now I rebuilt it. But this time it is under oil. Still, I only put insulation paper each 8 layers of 120 turns, or 960 turns. I'm trying to make my Tesla coil work, but the safety gap at the insulators keep firing all time and I have almost no sparks at the rotary gap. I just don't know what to do. If I open the safety gap a little more, I'm afraid it will fry it again.

Not sure if the oil will hold things up, since there is no paper between each wire layer, any idea? I know NSTs don't have any paper at all, but this thing can output some 300mA in a short circuit. Would the load from rotary spark gap and capacitors, prevent the internal arcing and destruction?