Author Topic: A few questions  (Read 7748 times)

Offline davekni

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Re: A few questions
« Reply #20 on: May 26, 2023, 09:00:32 PM »
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I am just assembling the UD 2.9 and I have almost all parts I need to finish it... except for three resistors - R13/R25 1.8K Ohm, R11 5.1Ohm and R3 51Ohm. Do I need to be precise with those resistors and their values or can I vary a little bit like e.g. using 2 10 Ohm or 2 100 Ohm in parallel or one 1K Ohm and one 750 Ohm in series?

And for the 51 Ohm the BOM says metal film... does it have to be metal film (if yes, why) or can I use carbon film resistors too? Just asking because I could still order carbon film type at Amazon and get them delivered tomorrow.
Presuming I'm looking at the same UD2.9 schematic:
R13 sets maximum OCD threshold (top voltage of 10k POT RV1).  Range looks too high on UD2.9 in my opinion, since dividing from 12V rather than 5V or 9V as in other driver designs.  So I'd use a larger value for R13, 5k or 10k.
R25 is a pull-up resistor, so not critical.  2k or even 3k would work.
R11 (and R12 which you didn't mention) are OCD CT burden resistors.  Calculate what current your CT will generate at your intended OCD limit.  Then pick a resistance that gives a reasonable voltage (say 5V) at that current, for the parallel combination of R11 and R12.  Doesn't need to be close to 5.1 ohms, but does need calculating.
R3 is the feedback CT burden resistor.  It needs to handle high peak power, so must be a resistor type appropriate for high peak power.  How high depends on your primary current and feedback CT ratio.

Sounds like you are in a hurry.  That can lead to problems.  Relax and think things through.  (BTW, I'll not be around to answer for a few days.)

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And... would you recommend using DIP sockets for the the ICs on the UD2.9 or is the driver robust at all, so that I don't need to expect the ICs like the 74s getting fried for whatever reason... I don't know how to be honest, but while dealing with the OneTesla type of driver I somehow managed to send those HCT74s and HC14s to hell on a daily basis
No clear answer that I know.  Sockets add inductance to IC pins, especially power pins, so can cause problems.  Adds thermal resistance too, important only for the UCC driver chips.  I'd not socket UCC driver chips, even though those are more likely to be ones to fry.  Depending on the socket and chips, sometimes bad socket connections can also cause hard-to-diagnose problems.

Hope your build goes well!
David Knierim

Offline ako

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Re: A few questions
« Reply #21 on: May 27, 2023, 12:42:13 AM »
Dude... First of all - You are awesome!

Thanks for having a look at the schematics and for the very detailed explanation regarding the resistors. That already helped me a lot and gave me a direction to head to and do more closer reading and understanding.

I am not in a hurry... it's just the little kid in me who gets excited. As long as the other old working and money earning guy in me can afford that little boys excitement, it's all fine. That's also how I got where I am with my skills today... Since my early childhood I always broke stuff first before I actually learned how it's working while trying to repair it again.

What you say about the IC sockets sounds damn right and I'll leave them out on this build (I still have 4 more spare PCBs to learn from and do it better in case it's the wrong decision). During the first build I really had that feeling that every now and then something fried just because I had touched some pins of the ICs with the oscilloscope probe.

I guess the next task for me to do now is to get how to measure the primary current and do some math. Measuring the currents is something I lacked the motivation for till now. I know that's something essential to do and I guess I reached the point of no return. Have to go that way now.

Offline davekni

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Re: A few questions
« Reply #22 on: May 30, 2023, 01:48:06 AM »
Quote
During the first build I really had that feeling that every now and then something fried just because I had touched some pins of the ICs with the oscilloscope probe.
Yes, slipping with a scope probe tip is an easy way to fry parts, primarily parts with more power than just logic ICs, such as gate drivers.  I fried a gate driver that way on my DRSSTC during initial check-out.

Quote
I guess the next task for me to do now is to get how to measure the primary current and do some math.
Measuring will be helpful later for debug.  Initially it is more important to decide how much current your IGBTs are capable of.  I think Mads has a guide for typical IGBTs used here.  My rule-of-thumb for TO247 packaged parts is that they fry at 2x rated peak current or 4x rated continuous current, given the soft-switching of DRSSTC use.  OCD limit is intended to prevent IGBT failure, so usually set based on IGBT capability rather than by measured current.
David Knierim

Offline ako

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Re: A few questions
« Reply #23 on: May 30, 2023, 10:43:53 AM »
Alright then...

Just received another batch of 10 FGA60N65SMD IGBTs a few minutes ago... I think 300A seems to be a good value to work with like this guy here http://www.personal.psu.edu/ahy5028/DRSSTC1.htm I found via Mads' design guide. I have almost exactly the same values. I didn't bother to convert his imperial and AWG wire values to metric but the resonant frequencies are in the same range. I measured 272kHz for my secondary with topload and a wire as streamer simulator and I've wound a flat primary which I measured 243kHz for at that clamp point you can see here... (UD 2.9 also almost finished, LM311 is missing which I should get tomorrow)



So... 300A...

Quote
Calculate what current your CT will generate at your intended OCD limit.  Then pick a resistance that gives a reasonable voltage (say 5V) at that current, for the parallel combination of R11 and R12.  Doesn't need to be close to 5.1 ohms, but does need calculating.

If I have a 1:1000 CT (1:33:1:33), do I get ~0.3A and need 16.66Ohm resistance to get a 5.0V signal? Is that math correct? I have to check how much voltage the input of LM311 tolerates right, to know the maximum R value I can use?
« Last Edit: May 30, 2023, 10:51:22 AM by ako »

Offline davekni

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Re: A few questions
« Reply #24 on: June 01, 2023, 04:27:21 AM »
Quote
If I have a 1:1000 CT (1:33:1:33), do I get ~0.3A and need 16.66Ohm resistance to get a 5.0V signal? Is that math correct? I have to check how much voltage the input of LM311 tolerates right, to know the maximum R value I can use?
BTW, 33 * 33 = 1089:1 CT ratio.  Close enough.
Yes, any resistor in the 10 to 20 ohm range would be fine.  Default UD2.* values tend to be for large coils using IGBT bricks for H-bridge.

Presuming same ratio for feedback CT, ~0.3A across 51 ohm is plenty low, so likely any 1W or 2W resistor is likely fine.
« Last Edit: June 01, 2023, 04:29:37 AM by davekni »
David Knierim

Offline Boilerbots

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Re: A few questions
« Reply #25 on: June 01, 2023, 07:11:05 AM »
You could have purchased most parts you need to assemble a fully working DRSSTC through ebay or Aliexpress if you just want to get something running and play around with it. This is what I was thinking when you first started asking about the oneTesla kits. There are quite a few kits of fully working TCs on there.

Offline ako

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Re: A few questions
« Reply #26 on: June 01, 2023, 02:57:06 PM »
Quote
BTW, 33 * 33 = 1089:1 CT ratio.  Close enough.
Yes, any resistor in the 10 to 20 ohm range would be fine.  Default UD2.* values tend to be for large coils using IGBT bricks for H-bridge.

Cool, seems I am on the right path then... In order to make use of 5W 15Ohm resistors (being in that resistance range and as I have a few of those) I rewound the CTs with a ratio of 1:625... which should be 0,48A if I remember well. So using another 15 Ohm as burden resistor for feedback should also be fine I guess, right? At least feedback seems to work very well per my tests with a signal generator running at my primary resonance frequency and scoping the gate signals.

 [ You are not allowed to view attachments ]

I still have to add the burden resistor and then I can start to do some initial tests. Will be a good opportunity to do first screenshots from my scope I recently bought... which brings me to:

Quote
You could have purchased most parts you need to assemble a fully working DRSSTC through ebay or Aliexpress if you just want to get something running and play around with it. This is what I was thinking when you first started asking about the oneTesla kits. There are quite a few kits of fully working TCs on there.

I know I could have done that... but I didn't... and passed the point of no return months ago.
« Last Edit: June 01, 2023, 03:01:43 PM by ako »

Offline davekni

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Re: A few questions
« Reply #27 on: June 01, 2023, 07:32:38 PM »
Quote
So using another 15 Ohm as burden resistor for feedback should also be fine I guess, right?
Might be fine.  Issue with low feedback burden resistor value is startup.  At beginning of each enable pulse, first half-cycle of output needs to generate enough feedback signal to generate the next half-cycle.  Especially for any testing at low H-bridge bus voltage, feedback amplitude of first half-cycle might be insufficient.  Feedback amplitude will be plenty high across 15 ohms once primary current builds up for a few cycles.
One way to fix startup issues is with self-oscillating mod's I've posted for UD2.7 (same feedback input circuit as UD2.9).  However, for your first coil, custom modifications add too much complexity.

Quote
Will be a good opportunity to do first screenshots from my scope I recently bought.
Great to hear that you have a scope.  That is a critical tool to get coils running.

I noticed screw terminals for your IGBT leads.  Makes changing parts easy, but also increases chances you will need to change parts.  Added lead inductance causes problems.  Primary issue is emitter lead inductance.  High emitter current causes voltage drop along lead.  That voltage gets subtracted from gate signal, distorting Vge.  Bridge ECB layout can add even more parasitic inductance.  I can't tell from the one image how your ECB looks.  BTW, just for reference, here's my tutorial on low-parasitic-inductance half-bridge construction:
https://highvoltageforum.net/index.php?topic=1324.msg9795#msg9795
David Knierim

Offline ako

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Re: A few questions
« Reply #28 on: June 01, 2023, 08:29:30 PM »
Quote
Might be fine.  Issue with low feedback burden resistor value is startup.  At beginning of each enable pulse, first half-cycle of output needs to generate enough feedback signal to generate the next half-cycle.  Especially for any testing at low H-bridge bus voltage, feedback amplitude of first half-cycle might be insufficient.  Feedback amplitude will be plenty high across 15 ohms once primary current builds up for a few cycles.
One way to fix startup issues is with self-oscillating mod's I've posted for UD2.7 (same feedback input circuit as UD2.9).  However, for your first coil, custom modifications add too much complexity.
I guess I am just experiencing exactly that... since the last picture I added the 15Ohm burden and a heatsink to those voltage regulators as those get pretty hot, barely to touch. Now hooked up everything again with the signal generator through the CT but don'T get anything on the gates.
Checked the 3 voltages rails and those are fine... 5, 12 and 24 Volts where they belong to. How do I calculate the burden resistance I'll at least / at maximum need? How are the rules there? What voltage/current do I need to achieve at which point?

And I am also not sure about all of those jumpers I can place to enable/disable/set some stuff... Most of them I do get... But a few are missing descriptions on the schematics and don't know yet if placing a jumper enables or disables stuff.

Offline davekni

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Re: A few questions
« Reply #29 on: June 01, 2023, 09:34:26 PM »
Quote
I guess I am just experiencing exactly that... since the last picture I added the 15Ohm burden and a heatsink to those voltage regulators as those get pretty hot, barely to touch. Now hooked up everything again with the signal generator through the CT but don'T get anything on the gates.
Probably similar, but in this test case, issue would be 15 ohms loading signal generator output down to too low a voltage.  Measure voltage across UD2.9 CT input.  Voltage required to start is around 0.2V depending on forward drop of D5.

Quote
How do I calculate the burden resistance I'll at least / at maximum need? How are the rules there? What voltage/current do I need to achieve at which point?
Haven't seen any calculation guides for startup.  So here's a quick procedure:  Calculate primary impedance at resonant frequency.  First half-cycle current is half-bridge output voltage (half of Vbus) divided by primary impedance.  Voltage is burden resistance times current divided by CT ratio.  UD2.x requires about 0.2V to start.  To be more precise, measure voltage across D5 when quiescent.  Startup requires slightly more than D5 quiescent voltage.

Quote
And I am also not sure about all of those jumpers I can place to enable/disable/set some stuff... Most of them I do get... But a few are missing descriptions on the schematics and don't know yet if placing a jumper enables or disables stuff.
Many of the "jumpers" are scope test points, not intended for any jumpers to be installed.  Critical one is J4.  If L1 is not installed (no phase lead), then J4 must be shorted.
David Knierim

Offline ako

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Re: A few questions
« Reply #30 on: June 02, 2023, 02:33:51 AM »
OK... fried 2 IGBTs just by having gate drive running and scoping without any power on VBus. Happened while playing around with the frequency of the signal generator while scoping.

After that read the guide for UD 2.7 and specifically the point about C33 again closely. Compared the two schematics and C33 on UD 2.7 should be C11 on UD 2.9. Changed the 1nF cap I had put in according to BOM with an 220pF as suggested in the UD 2.7 guide for coils running above 200KHz. I think that seemed to have inproved the signal at the gates a little. Here it comes now, my first screenshot :)



This is without IGBTs installed. I guess as 24V gate voltage is over the maximum ratings anyways, any overshoot is likely to kill the gates. Should I also put at least a little power power on the VBus when scoping the gates? Honestly, I am a little bit afraid now to put in and fry another set of brand new IGBTs. Would it make sense to do the testing with lower gate voltage? Like perhaps 15V as in the OneTesla schematics?

Regarding the feedback burden resistor... in the meantime I had thought in the first OneTesla like build I was using a CT with a ratio of 1:300 and a 5W 1kOhm resistor, so now with 1:625 maybe 2 1kOhm in parallel should do the job... so if I'm not wrong I should have 10W 500Ohm now, which seems to be working well. Oscillation starts as soon as I start the interrupter.

Back to the screenshot:

Currently I have 10Ohm gate resistance... I also had tested 20Ohm (without iGBTs installed), which definitely had removed the ringing but not the over/undershoots. Is it OK to have more than 10 Ohm gate resistances? Everywhere I read 5 - 10 Ohm are the values to use.
« Last Edit: June 02, 2023, 02:37:25 AM by ako »

Offline davekni

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Re: A few questions
« Reply #31 on: June 02, 2023, 03:17:52 AM »
Quote
OK... fried 2 IGBTs just by having gate drive running and scoping without any power on VBus.
That is extremely rare.  Are you certain IGBTs are fried?  Which leads are open or shorted?

Quote
I guess as 24V gate voltage is over the maximum ratings anyways, any overshoot is likely to kill the gates.
Looks like you have TVS diodes to protect IGBT gates.  What value are the diodes?  Mads points out that IGBT gate oxide typically doesn't die until roughly 80V even though spec limit is usually +-20V.  Many coils intentionally run Vge at +-24V to achieve slightly higher peak current.

Quote
Regarding the feedback burden resistor... in the meantime I had thought in the first OneTesla like build I was using a CT with a ratio of 1:300 and a 5W 1kOhm resistor, so now with 1:625 maybe 2 1kOhm in parallel should do the job... so if I'm not wrong I should have 10W 500Ohm now, which seems to be working well. Oscillation starts as soon as I start the interrupter.
500 ohms will likely be problematic at 300A primary, 0.48A from CT, 240V across burden resistor.  Are you looking at a schematic for secondary current feedback?

Quote
Currently I have 10Ohm gate resistance... I also had tested 20Ohm (without iGBTs installed), which definitely had removed the ringing but not the over/undershoots. Is it OK to have more than 10 Ohm gate resistances? Everywhere I read 5 - 10 Ohm are the values to use.
Small (ie. TO247) IGBTs often need more than 10 ohms.  5-10 is good for larger bricks.  If I recall correctly, I've used 33 ohms for TO247 parts.  Depends on IGBT gate capacitance and needed dead time.  Gate resistor slows turn-on while parallel diode makes turn-off fast.
Measuring ringing and over/undershoot requires IGBTs to be inserted to have realistic gate capacitance.  Also requires good scoping technique, probe and its ground clip directly connected to IGBT leads with ground lead against probe, not forming a large loop to pick up magnetic fields.
David Knierim

Offline Boilerbots

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Re: A few questions
« Reply #32 on: June 03, 2023, 11:27:50 PM »

Quote
You could have purchased most parts you need to assemble a fully working DRSSTC through ebay or Aliexpress if you just want to get something running and play around with it. This is what I was thinking when you first started asking about the oneTesla kits. There are quite a few kits of fully working TCs on there.

I know I could have done that... but I didn't... and passed the point of no return months ago.

That is the "Sunk Cost Fallacy"  ::)

For my first coil I wanted to focus on the construction and operation of the whole thing even though I could have spent a massive amount of time laying out a PCB just for my bulk capacitors and the IGBT I selected, however even that is not trivial considering the operating currents involved and trying to minimize inductance.



Offline ako

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Re: A few questions
« Reply #33 on: June 04, 2023, 02:20:40 AM »
Quote
That is extremely rare.  Are you certain IGBTs are fried?  Which leads are open or shorted?
Not yet sure for all of them... one or two I had tested were shorted between gate and emitter.

Quote
500 ohms will likely be problematic at 300A primary, 0.48A from CT, 240V across burden resistor.  Are you looking at a schematic for secondary current feedback?
Ehm... nope, I am still on the UD2.9 from the DRSSTC board pack of Profdc. How much voltage should I aim for?

Quote
Looks like you have TVS diodes to protect IGBT gates.  What value are the diodes?  Mads points out that IGBT gate oxide typically doesn't die until roughly 80V even though spec limit is usually +-20V.  Many coils intentionally run Vge at +-24V to achieve slightly higher peak current.
Those bigger diodes diodes in series are bidirectional 1.5KE220CA across collector and emitter of the IGBTs. The smaller ones go parallel with the gate resistors, unidirectional 1N5818, which might have been the wrong ones for 24V what I just realize... right?
I think I had bought some bidirectional BZW0631B TVS diodes intended as TVS across gates and emitters which I haven't built in yet. Should I do so? Are those the right ones for that purpose?

Offline davekni

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Re: A few questions
« Reply #34 on: June 04, 2023, 04:09:52 AM »
Quote
Not yet sure for all of them... one or two I had tested were shorted between gate and emitter.
That is consistent with overvoltage on Vge.

Quote
Ehm... nope, I am still on the UD2.9 from the DRSSTC board pack of Profdc. How much voltage should I aim for?
All the UD2.7 and UD2.9 schematics I've seen use 51 ohms for feedback burden resistor.  Surprised you saw 500 ohms somewhere.  51 works for most designs.  I described calculating startup in reply 29.

Quote
Those bigger diodes diodes in series are bidirectional 1.5KE220CA across collector and emitter of the IGBTs. The smaller ones go parallel with the gate resistors, unidirectional 1N5818, which might have been the wrong ones for 24V what I just realize... right?
I think I had bought some bidirectional BZW0631B TVS diodes intended as TVS across gates and emitters which I haven't built in yet. Should I do so? Are those the right ones for that purpose?
1N5818 is fine for diode across gate series resistor.
BZW0631B is higher voltage than typically used for Vge protection, but will clamp well before 80V.  Much better than no Vge protection.  Would likely have prevented your previous IGBT failures.
David Knierim

Offline ako

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Re: A few questions
« Reply #35 on: June 05, 2023, 01:04:41 AM »
Alrighty...

First small light and first BOOM with UD 2.9... I SHOULD have considered cooling for the IGBTS just in case of being succesful and getting first light... or... shouldn't have turned all knobs in all directions right away like a lunatic.... but YEAHHH... first light!!!

So... now I have to figure out how to properly put a heatsink on those IGBTs...

Then? Whats next?  I guess tuning the primary... What is the correct way to do that? Another CT for scoping the feedback frequency? Or scope across feedback or OCD connectors?


Offline davekni

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Re: A few questions
« Reply #36 on: June 05, 2023, 01:41:45 AM »
Quote
Another CT for scoping the feedback frequency? Or scope across feedback or OCD connectors?
Most people seem to use an additional CT.  Not necessary presuming your existing CTs are properly made with ferrite (not powered iron) cores.  Scope across the UD.9 burden resistor (51 ohms usually), not directly across feedback CT input.  Scoping across CT input will include phase lead, so not be accurate.
David Knierim

Offline ako

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Re: A few questions
« Reply #37 on: June 13, 2023, 09:31:41 AM »
I see some music coming from somewhere!
/>
I can’t stop smiling!

Offline davekni

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Re: A few questions
« Reply #38 on: June 14, 2023, 03:50:08 AM »
Congratulations on getting your coil running!
David Knierim

Offline ako

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Re: A few questions
« Reply #39 on: June 14, 2023, 08:43:59 AM »
Thanks man!

I definitely wouldn't already be where I am now without all of your support!!! I really appreciate that!

Of course now a few other questions came up... First of all, my last pair of IGBTs is still alive and surviving daily runs of a few minutes. But another batch of 10 are going to arrive today...

So far, I went up to 150V displayed on my variac before I ran the coil, as the display isn't of any usage when the coil runs (just jumps around and shows garbage). I haven't measured the bus voltage during the runs, but as I currently have a voltage doubling config with the two caps over the bridge, I guess at 150V input I already should be over more than 230V right? Just asking because I am more than happy with what comes out at input 150V right now, so I was thinking if I could not use a voltage doubling config and so be able to run the coil directly from mains without having to modify much more than how it is right now. But then I am wondering how I connect the primary to the bridge as it is currently connected to the center point between the two caps in series.

Another question I have is regarding the primary resonant capacitor. I've built the coil like the OneTesla with its 0.068uF capacitance and also used the same capacitor, but what I did differently is I have used 4 of those capacitors in a 2S2P config... don't know why... does that make sense to do so? Or can I save me 3 caps and use them otherwise... which brings me to the next question, can I use those as snubber caps?

Those two huge bus caps are 450V 5600uF each... Are those values more than I need for this size of coil? Can i go for lower values and smaller sized caps?

Ahh... another one: In regards of measuring primary voltage and current during the runs, everyone is speaking of measuring the bridge output? What exactly is the bridge output in that terms? Is it before the resonant capacitor or behind?

I tried to scope the primary current and output voltage with the help of an CT with a 1R burden resistor attached to it which seems to work fine I guess (that's actually what you see on the scope in the video) and a probe attached to the bridge output (before the cap) and then tried to adjust phase lead with an self wound inductor which I can adjust from ~2mH up to ~17mH according to my LCR meter, but I couldn't see anything significantly changing in the waveforms. Is there any tutorial for dummies how to do the scoping (During the primary voltage scoping, I had disconnected ground lead from my scope power cord)

« Last Edit: June 14, 2023, 08:57:10 AM by ako »

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Re: A few questions
« Reply #39 on: June 14, 2023, 08:43:59 AM »

 


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post Re: Are TVS diodes necessary for full bridge?
[Solid State Tesla Coils (SSTC)]
Simranjit
June 14, 2024, 02:27:06 AM
post Re: Are TVS diodes necessary for full bridge?
[Solid State Tesla Coils (SSTC)]
davekni
June 14, 2024, 01:56:58 AM
post Are TVS diodes necessary for full bridge?
[Solid State Tesla Coils (SSTC)]
Simranjit
June 13, 2024, 11:21:46 PM
post Re: Bigger sparks?...
[Vacuum Tube Tesla Coils (VTTC)]
Teslaventje
June 13, 2024, 08:50:56 PM
post Re: Steve Ward's DRSSTC Interrupter stops working when adjusting pulse width
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
June 13, 2024, 07:43:37 PM
post Re: Steve Ward's DRSSTC Interrupter stops working when adjusting pulse width
[Dual Resonant Solid State Tesla coils (DRSSTC)]
petespaco
June 13, 2024, 04:52:08 PM
post Re: Turning SSTC into DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
June 13, 2024, 02:14:17 AM
post Re: Turning SSTC into DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
June 12, 2024, 11:04:57 PM
post Turning SSTC into DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Simranjit
June 12, 2024, 10:23:08 PM
post Re: UD2.7C constantly in OCP despite having signal
[Dual Resonant Solid State Tesla coils (DRSSTC)]
verliebt_in_neukölln17
June 12, 2024, 08:41:06 PM
post Re: UD2.7C constantly in OCP despite having signal
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
June 12, 2024, 07:53:31 PM
post Re: Van de Graaf Voltage measurement with voltage sensor and voltage divider
[Static Electricity]
haversin
June 12, 2024, 06:57:13 PM
post UD2.7C constantly in OCP despite having signal
[Dual Resonant Solid State Tesla coils (DRSSTC)]
verliebt_in_neukölln17
June 12, 2024, 06:54:49 PM
post Re: Van de Graaf Voltage measurement with voltage sensor and voltage divider
[Static Electricity]
Mads Barnkob
June 12, 2024, 03:47:28 PM
post Van de Graaf Voltage measurement with voltage sensor and voltage divider
[Static Electricity]
vK
June 12, 2024, 03:42:18 AM
post Re: Bigger sparks?...
[Vacuum Tube Tesla Coils (VTTC)]
davekni
June 12, 2024, 03:32:22 AM
post Re: Bigger sparks?...
[Vacuum Tube Tesla Coils (VTTC)]
Teslaventje
June 11, 2024, 11:05:49 PM
post Re: Bigger sparks?...
[Vacuum Tube Tesla Coils (VTTC)]
MRMILSTAR
June 11, 2024, 05:36:46 AM
post Re: Sling Psychrometer
[Laboratories, Equipment and Tools]
Twospoons
June 11, 2024, 12:29:31 AM
post Bigger sparks?...
[Vacuum Tube Tesla Coils (VTTC)]
Teslaventje
June 10, 2024, 11:05:55 PM
post Re: Syntherrupter - A Feature-rich, Polyphonic Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
June 10, 2024, 10:57:51 PM
post Re: Benjamin's DRSSTC3
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
June 10, 2024, 08:08:04 PM
post Re: Plasma Torid - Class E Self Resonant Dual/Stereo - Plasma Torid Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hi-Deff
June 10, 2024, 06:04:09 PM
post Sling Psychrometer
[Laboratories, Equipment and Tools]
klugesmith
June 10, 2024, 04:43:59 PM
post Re: Benjamin's DRSSTC3
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
June 10, 2024, 03:35:28 PM
post Re: Benjamin's DRSSTC3
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Jj
June 10, 2024, 01:36:41 PM
post Re: Is a 60UF 800VDC Dawncap good for an induction heater?
[General Chat]
Anders Mikkelsen
June 09, 2024, 05:44:29 PM
post Is a 60UF 800VDC Dawncap good for an induction heater?
[General Chat]
yourboi
June 09, 2024, 03:31:30 PM
post Re: Steve Ward's DRSSTC Interrupter stops working when adjusting pulse width
[Dual Resonant Solid State Tesla coils (DRSSTC)]
NyaaX_X
June 09, 2024, 01:34:49 PM
post Steve Ward's DRSSTC Interrupter stops working when adjusting pulse width
[Dual Resonant Solid State Tesla coils (DRSSTC)]
verliebt_in_neukölln17
June 09, 2024, 01:56:51 AM
post Re: Return of Electronics Flea Market in "Silicon Valley"
[Sell / Buy / Trade]
klugesmith
June 08, 2024, 06:06:25 AM
post Re: Coulometric hourmeters
[Laboratories, Equipment and Tools]
klugesmith
June 08, 2024, 05:38:14 AM
post Interrupter for SSTC
[Beginners]
Simranjit
June 08, 2024, 12:47:47 AM
post Re: Adding capacitor to primary in SSTC
[Solid State Tesla Coils (SSTC)]
Michelle_
June 07, 2024, 03:59:57 PM
post Re: Adding capacitor to primary in SSTC
[Solid State Tesla Coils (SSTC)]
davekni
June 07, 2024, 06:42:26 AM
post Re: Space-X Starship test this week
[Science, Research and News In Other Fields Than Electronics]
MRMILSTAR
June 07, 2024, 05:08:00 AM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
davekni
June 07, 2024, 03:16:31 AM
post Re: Space-X Starship test this week
[Science, Research and News In Other Fields Than Electronics]
klugesmith
June 06, 2024, 11:37:20 PM
post Adding capacitor to primary in SSTC
[Solid State Tesla Coils (SSTC)]
Simranjit
June 06, 2024, 11:20:23 PM
post Re: Plasma Torid - Class E Self Resonant Dual/Stereo - Plasma Torid Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
June 06, 2024, 10:54:48 PM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
ZakW
June 06, 2024, 05:17:02 AM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
Simranjit
June 06, 2024, 04:50:00 AM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
davekni
June 06, 2024, 04:00:52 AM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
ZakW
June 06, 2024, 01:43:41 AM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
Simranjit
June 05, 2024, 11:11:17 PM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
Michelle_
June 05, 2024, 10:18:57 PM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
Simranjit
June 05, 2024, 10:13:03 PM
post Re: Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
ZakW
June 05, 2024, 09:29:18 PM
post Half bridge sstc different waveform on two mosfets
[Solid State Tesla Coils (SSTC)]
Simranjit
June 05, 2024, 08:46:53 PM
post Re: Want to build HV HF oscilloscope probe.
[Electronic Circuits]
Twospoons
June 05, 2024, 07:04:45 AM
post Re: Want to build HV HF oscilloscope probe.
[Electronic Circuits]
Domo
June 05, 2024, 04:58:35 AM
post Re: Pearson current monitor model 1330 teardown (100kA)
[Laboratories, Equipment and Tools]
klugesmith
June 05, 2024, 01:42:04 AM
post Re: Coulometric hourmeters
[Laboratories, Equipment and Tools]
klugesmith
June 04, 2024, 10:31:58 PM
post Re: My completed 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
pete_dl
June 04, 2024, 08:08:28 PM
post Re: Want to build HV HF oscilloscope probe.
[Electronic Circuits]
Twospoons
June 03, 2024, 11:13:26 PM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
June 03, 2024, 10:35:57 PM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hi-Deff
June 03, 2024, 05:51:05 PM
post Re: Want to build HV HF oscilloscope probe.
[Electronic Circuits]
Domo
June 03, 2024, 07:41:41 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
June 03, 2024, 05:28:44 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 03, 2024, 05:02:19 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
June 03, 2024, 03:47:33 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
June 03, 2024, 02:23:58 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hi-Deff
June 03, 2024, 01:25:24 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
June 03, 2024, 01:08:47 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 02, 2024, 10:29:02 PM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
Michelle_
June 02, 2024, 10:02:45 PM
post Re: Racing sparks
[Spark Gap Tesla Coils (SGTC)]
davekni
June 02, 2024, 08:25:37 PM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
Michelle_
June 02, 2024, 04:51:58 PM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Michelle_
June 02, 2024, 04:44:30 PM
post Re: My completed 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
MRMILSTAR
June 02, 2024, 03:25:11 PM
post APC Smart-UPS 1500VA Teardown
[Electronic Circuits]
Mads Barnkob
June 02, 2024, 01:36:11 PM
post Re: My completed 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
pete_dl
June 02, 2024, 11:43:40 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
June 02, 2024, 08:49:11 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
June 02, 2024, 08:36:07 AM
post Re: RDRSSTC - Project Build
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ZakW
June 02, 2024, 12:41:50 AM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
Benjamin Lockhart
June 01, 2024, 08:24:35 PM
post Pearson current monitor model 1330 teardown (100kA)
[Laboratories, Equipment and Tools]
Mads Barnkob
June 01, 2024, 08:22:28 PM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
Michelle_
June 01, 2024, 03:56:53 AM
post Re: Racing sparks
[Spark Gap Tesla Coils (SGTC)]
Terry
June 01, 2024, 12:03:50 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hi-Deff
May 31, 2024, 11:46:20 PM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
Michelle_
May 31, 2024, 06:13:59 PM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
May 31, 2024, 01:55:22 AM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
May 30, 2024, 11:57:49 PM
post Re: First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
May 30, 2024, 11:50:06 PM
post First DRSSTC questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hi-Deff
May 30, 2024, 11:23:35 PM
post Re: Steve Ward SSTC5 build
[Solid State Tesla Coils (SSTC)]
davekni
May 30, 2024, 10:43:06 PM
post Re: Benjamin's DRSSTC3
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
May 30, 2024, 10:24:35 PM
post Re: SSTC tripping circuit breaker
[Solid State Tesla Coils (SSTC)]
NyaaX_X
May 30, 2024, 06:10:04 PM

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