Author Topic: Project: FreakyDRSSTC MK1  (Read 2805 times)

Offline GrantV

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First power on tests
« Reply #20 on: March 03, 2021, 06:26:23 PM »
Hi there,

My build is coming along nicely and I was able to do my initial power on tests today!



After having to correct the phasing of my feedback CT, it rang up nicely :-)


Vin is just 16V DC using my trusty Lipo battery :-)

I do have an issue that I am going to have to look at though, as the OCD CT is arcing under the CT to the track on the PCB .... not sure why, but I'll desolder it later and see what is going on  :-\

Another issue that is concerning me is the BPS ........ with the interrupter set at minimum (supposedly 10 to 20BPS), my scope shows just 800uS between bursts which would be 1.2KHz?



Am I reading this correctly or have I missed something? I would hate to move on to higher power testing and blow my IGBT's due to the increased duty cycle........
« Last Edit: March 03, 2021, 06:39:14 PM by GrantV »

Offline davekni

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Re: Project: FreakyDRSSTC MK1
« Reply #21 on: March 04, 2021, 04:47:32 AM »
Is your CT between MMC and primary coil?  That wire has high voltage, so isn't good for CT placement.  The other possibility is a bad connection or failed component in the OCD diode bridge or burden resistor.  An unloaded CT will generate high voltage spikes at each zero-crossing.  May be damaging the CT internally too.

Looks like your controller has a problem with 1.25kHz minimum frequency.  Definitely fix that before increasing power.
David Knierim

Offline GrantV

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Re: Project: FreakyDRSSTC MK1
« Reply #22 on: March 04, 2021, 11:15:01 AM »
Is your CT between MMC and primary coil?  That wire has high voltage, so isn't good for CT placement.  The other possibility is a bad connection or failed component in the OCD diode bridge or burden resistor.  An unloaded CT will generate high voltage spikes at each zero-crossing.  May be damaging the CT internally too.

Looks like your controller has a problem with 1.25kHz minimum frequency.  Definitely fix that before increasing power.

Hi David,

No, the CT is not between the MMC and primary, it is however on the opposite leg to the feedback CT, which I do not think should be a problem.

I think you nailed it however regarding the unloaded CT! Desoldering the CT showed a carbon arc trace between one of the pins and the opposite pins trace which I had inadvertantly (stoopidly) placed on the top of the board and routed it just a mm from the pin! Doing my first tests I unplugged the CT and used that line to push a signal into the driver from my sig gen ... the CT thus ran unloaded .....



Happily however, it doesn't seem like I have damaged the CT itself as I have now wired it up directly off-board and it is working fine. So I live and learn :-)

The interrupter issue is ongoing ....
« Last Edit: March 04, 2021, 11:20:01 AM by GrantV »

Offline davekni

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Re: Project: FreakyDRSSTC MK1
« Reply #23 on: March 04, 2021, 10:18:32 PM »
Opposite sides of H-Bridge is no issue.

The 1mm gap isn't a problem either.  The problem is having no load on the CT secondary.  A burden resistor or shorting-strap or other load on the "CT 2 OUT" connector is necessary whenever running.  Or, if you want to make that board robust to unconnected CT load, add TVS diode(s) across the CT secondary.  (TVS diode capacitance is generally high, so that could affect phasing a bit if used on the feedback CT.)

That 1mm gap may have saved your CT from damage.  Sometimes intentional spark gaps are added to circuit boards as over-voltage protection.  The 1mm gap sparked over before voltage became high enough to spark inside the CT.
« Last Edit: March 04, 2021, 10:27:28 PM by davekni »
David Knierim

Offline GrantV

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Re: Project: FreakyDRSSTC MK1
« Reply #24 on: March 05, 2021, 09:55:49 AM »
Opposite sides of H-Bridge is no issue.

The 1mm gap isn't a problem either.  The problem is having no load on the CT secondary.  A burden resistor or shorting-strap or other load on the "CT 2 OUT" connector is necessary whenever running.  Or, if you want to make that board robust to unconnected CT load, add TVS diode(s) across the CT secondary.  (TVS diode capacitance is generally high, so that could affect phasing a bit if used on the feedback CT.)

That 1mm gap may have saved your CT from damage.  Sometimes intentional spark gaps are added to circuit boards as over-voltage protection.  The 1mm gap sparked over before voltage became high enough to spark inside the CT.

Hey David.

So what you are actually saying, is that I am soooo extremely clever that I subconciously added a safety feature to my board and then ran the CT unloaded JUST to test the efficacy of that safety feature? NICE! Cheers for that  ;D

Seriously though, thanks for your reply and the info! Learning through mistakes is made a lot easier when someone takes the time to explain properly!

If or when I do do a rework of the board I think I would opt to add an intentional spark gap for each of the CT's on a visible section of the board rather than add additional components. The only reason it took me a while to figure out what was going on was because as much as I could hear the HF crackling, I couldn't see the arcing under the CT until I switched the lights off and went searching for the source of the offending sounds :-)

Offline davekni

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Re: Project: FreakyDRSSTC MK1
« Reply #25 on: March 05, 2021, 07:05:38 PM »
Yes, exactly, you added a safety feature :)

Even with an intentional spark gap, always connect the CT output to the driver or with a shorting strap.  The spark gap should be there to handle only mistakes such as a broken connector wire.
David Knierim

Offline GrantV

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Update
« Reply #26 on: March 10, 2021, 01:26:10 PM »
Ok, so I have decided to throw the CloudLeopard Yunbao driver and interrupter in the spare parts bin as I am getting nowhere with it! (cannot get the BPS below 1250Hz)

I have gone ahead and ordered all the components I need to build up my Loneoceans UD2.7C driver, and those should be arriving in the next few days.

My budget is now however very sadly lacking, so as much as I would like to buy a OneTesla or EVR interrupter, I honestly just do not have the cash for that right now :-(

What is your favorite "lower cost" interrupter?

« Last Edit: March 10, 2021, 05:03:16 PM by GrantV »

Offline Max

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Re: Project: FreakyDRSSTC MK1
« Reply #27 on: March 10, 2021, 05:32:51 PM »
It takes quite some effort to say this (joking) but I guess the best bang per buck interrupter is the MidiStick from TMaxElectronics: https://highvoltageforum.net/index.php?topic=1117.0
I'd normally recommend my own work (ofc  ;D) but since your budget is limited that wouldn't make any sense; the build costs start at about 80$.
There are of course more interrupters out there. Some are listed in this topic: https://highvoltageforum.net/index.php?topic=573.0

Aaand there are the simpler old school interrupters which are based on 2-3 NE555 chips like this one from Steve Ward: https://stevehv.4hv.org/drsstc_interrupter.htm No MIDI and not expensive


Kind regards,
Max
« Last Edit: March 10, 2021, 05:35:21 PM by Max »

Offline Mads Barnkob

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Re: Project: FreakyDRSSTC MK1
« Reply #28 on: March 11, 2021, 10:32:42 AM »
Aaand there are the simpler old school interrupters which are based on 2-3 NE555 chips like this one from Steve Ward: https://stevehv.4hv.org/drsstc_interrupter.htm No MIDI and not expensive

In Profdc9's PCB pack there is a combined Steve Ward interrupter, audio interrupted and onetesla MIDI interrupted on one PCB: https://highvoltageforum.net/index.php?topic=353.msg2401#msg2401

Another cheap and old-school audio interrupter: https://kaizerpowerelectronics.dk/tesla-coils/musical-sstcdrsstc-interrupter/
https://kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics
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Offline GrantV

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Re: Interrupter
« Reply #29 on: March 11, 2021, 02:00:35 PM »
Hi again,

Max and Mads, thanks for your replies :-)

Max, I absolutely love your Syntherrupter but will leave that for later when I have built up my funds again a bit :-)

Tmax has offered me one of his MidiSticks so I think I am going to go that route for the Midi interface!

Since my post yesterday, I have resurrected an old project I had been working on and after a bit of tinkering, it is now working quite well :-)



It is a STM32 F4 Black Pill with an old LCD panel, a 3 way switch (mode switch), a momentary push button (burst or pause depending on mode), 2 rotary encoders (BPS and pulse width) and a transistor driven output stage for the IF-E96E.

Now that it is working (even though the coding is very dirty and needs some work), it is successfully giving me a beautifully clean output with absolute control over the pulse width and the BPS in auto mode and is also working very nicely in burst mode with a single burst at the set pulse width.

Although it does show me the duty cycle on the screen, I am yet to implement a max duty cycle limiter.

I'll carry on working on it and report back :-)

OH .... and my parcel has just arrived from DigiKey so I'll be able to start the build of my UD2.7C driver as well :-)
« Last Edit: March 11, 2021, 06:27:57 PM by GrantV »

Offline GrantV

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Duty Cycle Limiter
« Reply #30 on: March 11, 2021, 06:25:04 PM »
OK, I need more help please :-)

I am trying to decide on what my max duty cycle should be and how to implement a limiter in the code.

Is there a simple rule-of-thumb for TO-247 IGBT coils that I could use?

OR

Do I need to set it up based on actual coil parameters?

I have spent the last 30minutes reading through Mads https://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/igbts/ but I am probably more confused now than when I started  ;D

Next:
To the coders out there, how have you implemented your active max duty cycle limiter? My thinking at this point is that :
Case 1: Duty cycle is set and the operator is busy increasing the BPS - when max duty cycle is reached the code activelt decreases the pulse width while alowing BPS to be increased further.
Case 2: BPS is set and the operator is busy increasing the pulse width - when max duty cycle is reached the code actively decreases the BPS while allowing pulse width to be increased further.

OR, do you just set a hard limit and the operator has to manually lower one or other parameter?

OR, am I overthinking it entirely?

Offline Max

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Re: Project: FreakyDRSSTC MK1
« Reply #31 on: March 11, 2021, 07:23:22 PM »
Most coils - no matter their size - have their duty cycle limit somewhere around 10-20%. In the early days people tended to push their IGBTs really hard (like 2kA-through-a-300A-IGBT-hard). This causes extreme temperature spikes on the IGBT die which aren't measurable from the outside. The rule of thumb that DRSSTCs should be run at <=10% duty cycle comes from those setups. Today however most people don't push their IGBTs that hard anymore (todays IGBTs are different, too) and there are many coils out there running happily at 20% or even more. I'd suggest you monitor the temperature of your setup. Parts that can get (too) warm include IGBTs/heatsink, MMC, wiring in the primary circuit, the primary itself (especially the inner turn) and the secondary. As long as nothing is overheating you should be able to increase the duty. Depending on your setup your limiting factor might even be the circuit breaker  ::)

Now considering the code side... Since we're talking about a limiter I personally would prefer it to be just like a potentiometer that reached the end of the range, you can't turn it further (your third case). To keep the analogy, it would confuse me if hitting the end of a potentiometers range would start turning other pots. This is however a personal preference. After all, you're the one who will use it so you have to find out what you prefer. From a programming perspective there's not much difference between both, so you could try either one out.

I can see some use from what you describe as case 1 and in fact I implemented something similar in my Syntherrupter. Its Simple Mode (=simple interrupter like what you're doing here) has three sliders, ontime, BPS and duty cycle. And yes, this is redundant, so I need to decide what value gets adjusted when the user moves a slider. Instinctively I wouldn't expect the BPS to change if I mess with the duty or the ontime (which would be your case 2). Hence, if either the duty or the ontime slider changes, the other one is adjusted automatically. The more interesting scenario is a change of the BPS. In that case Syntherrupter keeps whatever value has been modified lastly. If the user sets an ontime, then moves the BPS slider, the duty cycle will adjust accordingly. And if he set the duty cycle before modifying the BPS, the ontime will adjust. I thought this was the most intuitive solution. On top of that, you have of course the ontime/bps/duty limitation, which as I said above only limits you without modifying anything. Once one of the sliders hits the end of its range no new value will be applied. To get a feeling of it, you can try it yourself; to run my UI you don't need to buy any hardware (Steps: 1. Download latest release, 2. Download Nextion Editor, 3. In the editor, hit "Debug" and select the Syntherrupter_Nextion_NX8048T050.tft file from the release zip file, 4. Write "click comOk,1" (without quotes) in the bottom left window and hit enter, 5. Have fun!).

Of course, if you don't like such hard limits, you could make your interrupter such that it always adjusts the oldest of the three values. Neither solution is harder than the other so I'd suggest you try a couple of them and find the one that suits you best.


Kind regards,
Max

Offline GrantV

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Re: Duty Cycle Limiter
« Reply #32 on: March 12, 2021, 09:30:20 AM »
Most coils - no matter their size - have their duty cycle limit somewhere around 10-20%. In the early days people tended to push their IGBTs really hard (like 2kA-through-a-300A-IGBT-hard). This causes extreme temperature spikes on the IGBT die which aren't measurable from the outside. The rule of thumb that DRSSTCs should be run at <=10% duty cycle comes from those setups. Today however most people don't push their IGBTs that hard anymore (todays IGBTs are different, too) and there are many coils out there running happily at 20% or even more. I'd suggest you monitor the temperature of your setup. Parts that can get (too) warm include IGBTs/heatsink, MMC, wiring in the primary circuit, the primary itself (especially the inner turn) and the secondary. As long as nothing is overheating you should be able to increase the duty. Depending on your setup your limiting factor might even be the circuit breaker  ::)

Now considering the code side... Since we're talking about a limiter I personally would prefer it to be just like a potentiometer that reached the end of the range, you can't turn it further (your third case). To keep the analogy, it would confuse me if hitting the end of a potentiometers range would start turning other pots. This is however a personal preference. After all, you're the one who will use it so you have to find out what you prefer. From a programming perspective there's not much difference between both, so you could try either one out.

I can see some use from what you describe as case 1 and in fact I implemented something similar in my Syntherrupter. Its Simple Mode (=simple interrupter like what you're doing here) has three sliders, ontime, BPS and duty cycle. And yes, this is redundant, so I need to decide what value gets adjusted when the user moves a slider. Instinctively I wouldn't expect the BPS to change if I mess with the duty or the ontime (which would be your case 2). Hence, if either the duty or the ontime slider changes, the other one is adjusted automatically. The more interesting scenario is a change of the BPS. In that case Syntherrupter keeps whatever value has been modified lastly. If the user sets an ontime, then moves the BPS slider, the duty cycle will adjust accordingly. And if he set the duty cycle before modifying the BPS, the ontime will adjust. I thought this was the most intuitive solution. On top of that, you have of course the ontime/bps/duty limitation, which as I said above only limits you without modifying anything. Once one of the sliders hits the end of its range no new value will be applied. To get a feeling of it, you can try it yourself; to run my UI you don't need to buy any hardware (Steps: 1. Download latest release, 2. Download Nextion Editor, 3. In the editor, hit "Debug" and select the Syntherrupter_Nextion_NX8048T050.tft file from the release zip file, 4. Write "click comOk,1" (without quotes) in the bottom left window and hit enter, 5. Have fun!).

Of course, if you don't like such hard limits, you could make your interrupter such that it always adjusts the oldest of the three values. Neither solution is harder than the other so I'd suggest you try a couple of them and find the one that suits you best.


Kind regards,
Max

Hi Max,

Thank you very much for your reply, it gives me a lot to think about and work with :-)

I'll most definitely have a play with your UI to see how you have implemented things!

I appreciate your comments on turning a pot or raising a slider till it hits it's maximum, however, as I have gone with digital encoders for my controls, there is no mechanical hard limit, which means that from a firmware point of view, the range for my encoders for BPS and on-time is from 1 to 4294967295 (uint32)  ;D I can of course set max parameters, but the point is that I do not have any mechanical limts.

Using encoders is great because it gives me very fine control of the parameters but also has the down side in that it takes many many turns to set higher values. I am sure it will be fun initially, but in the long run it may end up just being annoying, and I'll swop them out for pots LOL
« Last Edit: March 12, 2021, 09:47:53 AM by GrantV »

Offline Max

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Re: Project: FreakyDRSSTC MK1
« Reply #33 on: March 12, 2021, 10:23:44 AM »
Hi again,


I think you may have misunderstood my potentiometer analogy. I perfectly know that you can turn those things as far and as long as you like. However I personally wouldn‘t want it to start changing other values at some point in the endless scale. I would rather prefer nothing to change anymore if I try to turn past a limit. Of course I can continue to physically turn the knob but the effect is that I simply hit the end of the virtual range and cant go further.

Good point with having to turn a lot. I guess you have two options: If you want to have the full resolution across the entire range you need to implement some sort of velocity control. This means that you detect the turning velocity and increase the step size with the velocity (turn the encoder fast => sweep even faster through the range). From commercial products I know that this can result in a very intuitive control across the full range - no matter how many orders of magnitude the range covers. I also know that it can be annoying as f*** if it‘s not well done. So again, something you probably need to experiment with. I‘m pretty sure there are libraries out there that can do this, too.
The easier solution might be to implement something like a log potentiometer. So your step size simply depends on the range. That‘s what I have done with Syntherrupters sliders: 0-49: step size 1, 50-99: step size 5, 100-499: step size 10, 500-1000: step size 50, ...
this should be easier to implement while giving enough resolution (worst case is a step size of 10% of the current value). Of course, if you want to be able to control whether your ontime is 314 or 315 microseconds, this won‘t work for you.

Neither solution gives you a „continuous“ increase/decrease of the signal. If you‘d like to have a smooth transition from one value to another one I can recommend something like a moving average filter. My filter code (which is a bit more than only moving average) can be found here: https://github.com/MMMZZZZ/Syntherrupter/blob/dev/Syntherrupter_Tiva/Filter.cpp
For the ontime I use a filter with factor=2.0f, constant=30.0f, for the BPS I use factor=1.8f, constant=5.0f. Yet again, values to play with.


Kind regards,
Max

Offline GrantV

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Re: Project: FreakyDRSSTC MK1
« Reply #34 on: March 12, 2021, 12:20:19 PM »
Hey Max,

LOL sorry, no, I didn't misunderstand your pot analogy, I probably just did not answer correctly. It is early days for me as I have, as yet, never actually run or controlled a DRSSTC, so I am sure that my thinking and preferences will change once I get to testing in reality rather than just working with what is in my head *chuckle*

I have seen code snippets which implement velocity control, I have just not gone that route yet as my coding skills are rudimentary at best and it has all been a very steep learning curve!

I do currently have very basic step sizes implemented to lower the resolution but I have generally kept these at very low values during testing. Again, once I get the coil up and running I'll get a far better idea of what settings I prefer.

Your moving average filter sounds interesting, but to be honest, goes way over my head LOL

Offline TMaxElectronics

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Re: Project: FreakyDRSSTC MK1
« Reply #35 on: March 12, 2021, 12:24:04 PM »
Personally I consider your case 1 the best option, but primarily because I usually build musical interrupters where the note frequency is of course most important :D

The way I (and probably most others) have implemented is like this:
  • Compute the current duty cycle (frequency * on-time in sec) of each voice (one for you if I saw correctly)
  • Get the ratio between the maximum duty cycle and the current one (currDuty / maxDuty)
  • And finally multiply the actual on-time with that factor if it is < 1

As for the velocity control, you can just measure the time between each encoder pulse and use that to scale your counting speed (so like maxSpeed/time). Make sure you debounce the switches properly though, as it could otherwise just shoot up like crazy even when moving slowly ;)
And then you could of course also just dynamically calculate the maximums so you don't go over your maximum duty cycle. Basically just do a check every time the encoder increments to see if you have increased the value too far, and reset it if it is so.

Offline GrantV

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Aaaaarrrgghhhh
« Reply #36 on: March 19, 2021, 06:34:20 PM »
I am GUTTED!!!

Finally managed to get my UD2.7C all soldered up ...



BUT ... got the 9V regulator in the wrong way so when I tested, the 9V components got a few seconds of 24V!

I was hoping that nothing had been damaged but that does not seem to be the case.

After reorienting the 9V reg and reconnecting, the drive sends output to the GDT drivers wether or not I have signal from the interrupter and UVLO also does not cut the output.

So ... I now have some fault finding to do ....... Oh well, that's Monday's problem ...

OH .... and What does the jumper at JP1 do? Is it simply to enable/disable UVLO?
« Last Edit: March 19, 2021, 06:37:50 PM by GrantV »

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Re: Project: FreakyDRSSTC MK1
« Reply #37 on: March 19, 2021, 06:41:36 PM »
Oh dear oh dear, how much did that mistake cost?

Offline davekni

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Re: Project: FreakyDRSSTC MK1
« Reply #38 on: March 19, 2021, 07:41:28 PM »
Is the GDT output a clean 24V square wave?  If so, I'm guessing that your 9V regulator mistake didn't fry anything.  There is probably some other unrelated issue causing the driver to be always-enabled.  Measure 5V and 9V supplies to make sure they are both good now.

Yes, it looks like JP1 enables UVLO.

With the driver disabled (interrupter input low or UVLO output low), measure voltage through the enable path.  IC6-1 (clear-n) should be low, so IC6-5 (Q) should be low.  That should make IC6-10 high and IC6-13 low, which makes IC6-9 low (other Q).  Measure these voltages to see where something goes wrong.  If these are all good, then continue measuring through IC5.
David Knierim

Offline TMaxElectronics

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Re: Project: FreakyDRSSTC MK1
« Reply #39 on: March 19, 2021, 08:42:05 PM »
Sorry to hear that!

But as davekni said aswell I think that if there is a clean output coming out of the GDTs most parts are likely fine and the issue is either limited to borken parts in the interrupter input path or even just a bad solder joint there :)

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Re: Project: FreakyDRSSTC MK1
« Reply #39 on: March 19, 2021, 08:42:05 PM »

 


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post Re: Mitsubishi CM300DY-24H IGBT
[Beginners]
Mads Barnkob
April 18, 2021, 08:04:18 PM
post Mitsubishi CM300DY-24H IGBT
[Beginners]
thedoc298
April 18, 2021, 07:10:24 PM
post Re: gdt high frequency ring
[Solid State Tesla Coils (SSTC)]
balazs
April 18, 2021, 01:11:28 PM
post Re: Drsstc Driver Board for Tesla Coil Driver Optic Fiber Splice
[Dual Resonant Solid State Tesla coils (DRSSTC)]
iw1esu
April 18, 2021, 12:26:48 PM
post Re: Mains synced sstc questions
[Solid State Tesla Coils (SSTC)]
Magneticitist
April 18, 2021, 02:36:34 AM
post Re: Help needed with SSTC. First TC build
[Solid State Tesla Coils (SSTC)]
davekni
April 18, 2021, 01:24:59 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
mrsebe
April 17, 2021, 07:56:07 PM
post Re: Project: FreakyDRSSTC MK1
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
April 17, 2021, 07:50:17 PM
post Re: Help needed with SSTC. First TC build
[Solid State Tesla Coils (SSTC)]
Maverikie
April 17, 2021, 07:20:58 PM
post Re: Project: FreakyDRSSTC MK1
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GrantV
April 17, 2021, 11:53:37 AM
post Re: Help needed with SSTC. First TC build
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
April 17, 2021, 09:34:02 AM
post Re: Help needed with SSTC. First TC build
[Solid State Tesla Coils (SSTC)]
davekni
April 17, 2021, 05:36:49 AM
post Re: Project: FreakyDRSSTC MK1
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
April 17, 2021, 04:30:36 AM
post Help needed with SSTC. First TC build
[Solid State Tesla Coils (SSTC)]
Maverikie
April 16, 2021, 09:22:47 PM
post HELP .... PLEASE?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GrantV
April 16, 2021, 10:50:24 AM
post Re: Mains synced sstc questions
[Solid State Tesla Coils (SSTC)]
dexter
April 15, 2021, 10:48:12 PM
post Re: Drsstc Driver Board for Tesla Coil Driver Optic Fiber Splice
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
April 15, 2021, 01:57:49 PM
post Re: My 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
MRMILSTAR
April 14, 2021, 10:56:15 PM
post Re: My 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
MRMILSTAR
April 14, 2021, 09:34:11 PM
post Re: Single mosfet bifiliar gdt
[Solid State Tesla Coils (SSTC)]
aie212
April 14, 2021, 09:19:51 PM
post Re: My 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
304er
April 14, 2021, 07:54:38 PM
post Re: My 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
304er
April 14, 2021, 07:42:50 PM
post Re: Single mosfet bifiliar gdt
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
April 14, 2021, 07:39:14 PM
post Re: Mains synced sstc questions
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
April 14, 2021, 07:35:25 PM
post Re: My 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
davekni
April 14, 2021, 07:34:33 PM
post Mains synced sstc questions
[Solid State Tesla Coils (SSTC)]
costas_p
April 14, 2021, 05:00:12 PM
post Re: My 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
MRMILSTAR
April 14, 2021, 03:51:36 PM
post Re: Drsstc Driver Board for Tesla Coil Driver Optic Fiber Splice
[Dual Resonant Solid State Tesla coils (DRSSTC)]
GrantV
April 14, 2021, 11:40:45 AM
post Re: My 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
304er
April 14, 2021, 10:31:23 AM
post Re: My 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
304er
April 14, 2021, 10:03:39 AM
post Re: Secondary Resonant Circuit Size
[Beginners]
Mads Barnkob
April 14, 2021, 08:07:39 AM
post Re: Secondary Resonant Circuit Size
[Beginners]
davekni
April 14, 2021, 04:22:58 AM
post Re: Drsstc Driver Board for Tesla Coil Driver Optic Fiber Splice
[Dual Resonant Solid State Tesla coils (DRSSTC)]
iw1esu
April 14, 2021, 01:07:11 AM
post Secondary Resonant Circuit Size
[Beginners]
benet
April 13, 2021, 11:52:24 PM
post Re: My 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
MRMILSTAR
April 13, 2021, 10:17:24 PM
post Re: My 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
davekni
April 13, 2021, 09:47:39 PM

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