Author Topic: Piernas's Fast ZVS Mazzilli Driver  (Read 12352 times)

Offline neukyhm

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Piernas's Fast ZVS Mazzilli Driver
« on: December 22, 2018, 06:43:09 PM »
Hi everyone, I'm posting now part of the project https://highvoltageforum.net/index.php?topic=514.0
This is a Fast mod for the original ZVS.



The X-Ray machine has an ETD59 gapped core, and I had to drive it somehow. The problem was that the original Mazzilli driver is very slow at charging the Mosfet gates so I had to think a solution, and this was using a dual Mosfet driver, the TPS2814P. For more info, here is the hackaday.io page



This schematic is very useful if you're looking for a way to drive a HV transformer and your primary's inductance is low, making the resonant frequency too high for a regular ZVS driver. Hope you like it.



With this circuit I'm able to drive 150V across the primary, using two IRFP250N at 110kHz.

« Last Edit: January 01, 2019, 03:32:57 PM by neukyhm »

Offline Mads Barnkob

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #1 on: March 11, 2019, 09:04:04 AM »
This thread went under the radar for me, which is a shame, because a active drive addition to the Mazilli ZVS is a great improvement against cross-conduction failures at low input voltage.

Does it have built-in dead-time to avoid cross-conduction and possible improve it with a separate drive power supply with a large capacitance on it, in order to make sure that gate drive is the last to shut down when pulling the main power or tripping a breaker.

Thanks for sharing.
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Offline neukyhm

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #2 on: March 11, 2019, 05:02:06 PM »
This thread went under the radar for me, which is a shame, because a active drive addition to the Mazilli ZVS is a great improvement against cross-conduction failures at low input voltage.

Does it have built-in dead-time to avoid cross-conduction and possible improve it with a separate drive power supply with a large capacitance on it, in order to make sure that gate drive is the last to shut down when pulling the main power or tripping a breaker.

Thanks for sharing.
Hi Mads :P

I'm not an expert on this stuff (I'm a physicist not an electronics engineer). With "dead-time" and "cross-conduction", you mean to avoid enabling both Mosfets at the same time?

Talking now about the driver being the last thing to turn off, this circuit is inside the x-ray machine, that also has 2 relays, one of them is for the filament and the other feeds the Mosfet driver of the ZVS. I programmed the arduino board to first shutdown the main 48V psu via TTL signal, waits 200ms, and then shutdown the relay that feeds the Mosfet driver, this way any energy left in the LC circuit of the ZVS will leave through a fully ON Mosfet.

Offline Hydron

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #3 on: March 12, 2019, 10:18:03 AM »
I'm not an expert on this stuff (I'm a physicist not an electronics engineer). With "dead-time" and "cross-conduction", you mean to avoid enabling both Mosfets at the same time?
That's exactly what it means - deadtime is the enforced period between the top switch turning off and the bottom turning on (or vice versa), while cross-conduction is what happens when both end up on at the same time, shorting out the supply (generally a bad thing :P)

Offline Mads Barnkob

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #4 on: March 12, 2019, 01:06:39 PM »
Now I had time to look up the datasheet for the TPS2814P ( https://datasheet.octopart.com/TPS2811P-Texas-Instruments-datasheet-69875.pdf ) and it says just in the description "...a design that inherently minimizes shoot-through current..." and on page 7 is a table over the typical propagation delay times, which is 25-35ns between input/output and that should hinder most cross-conduction, which shoot-through is a word for the same.
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Offline neukyhm

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #5 on: March 12, 2019, 02:06:00 PM »
I didn't know about cross-conduction and deadtime. I did know that I had to take care that there is only one Mosfet enabled at the same time, and also to avoid that there is none enabled, because the inductor in all Mazzilli drivers will cause a voltage peak to both Mosfets, I could see this in the oscilloscope.

As far as I understand, there is no way to fully prevent cross-conduction, right? the turning ON process of a transistor is not immediate, not in real life.

Offline flyrod

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #6 on: March 13, 2019, 02:35:03 AM »
I missed this thread before too, but thanks for sharing your results!  Do you have any traces of the gate signal(s)?  Also, can you talk some about how you picked the various resistor values?  Are they just what you had or did they need to be tuned using the oscilloscope?  I've found these circuits to be very sensitive to the particular components and layout, so without a scope it's mostly trial and error for me.

Offline neukyhm

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #7 on: March 13, 2019, 04:24:18 PM »
I missed this thread before too, but thanks for sharing your results!  Do you have any traces of the gate signal(s)?  Also, can you talk some about how you picked the various resistor values?  Are they just what you had or did they need to be tuned using the oscilloscope?  I've found these circuits to be very sensitive to the particular components and layout, so without a scope it's mostly trial and error for me.

This is the signal to the input of the Mosfet driver:


There is a peak at the beginning that I suspect it's caused by the UF4007 when they block current suddenly so a voltage peak it's produced there, but the TPS2814P manages it well.

This is the mosfet's gate signal at 200W:


There is ringing, but the mosfets stay cold. This is a stress test I did at high power (200W) but the x-ray machine is below 100W. At less power, the ringing is also smaller, but it's frequency what contributes the most to it. The frequency here is high (>100kHz).

Talking about the resistors, I knew that a big resistor at the IC inputs would reduce ringing there, but these inputs also has a capacitance, so a big resistor would have made the input activation a bit slower, I chose 1k because they worked well. I also placed 100ohm resistors next to the diodes because I could see that the fast ringing seen at the gates when turning off was caused by the 100mH inductor in all ZVS. I could see that, at the exact time mosfets are switching, this inductor causes a voltage peak to both drains that also block both diodes, and this causes a small voltage peak at the IC inputs, I could see that placing a 100ohm ressitor there reduced this noise a lot, I think it's because that resistors make the IC inputs discharge just a bit slower (due to the input capacitance), so the turning off process is delayed some nanoseconds and the other mosfet has time to turn ON, preventing the scenario where mosfets are switching and we can't consider yet that one of them is fully on, so the voltage peak produced by the 100mH inductor is smaller.

This is hard to explain and harder to understand, I had to think a lot what was causing that noise when the mosfet is turning off, until I discovered that the 100mH inductor was causing it.

Offline flyrod

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #8 on: March 14, 2019, 04:25:24 PM »
Thanks for the detailed reply!  I wonder how much of that ringing is really there.  Have you seen this AN?

https://www.onsemi.com/pub/Collateral/AN-9005.pdf.pdf

You can get noticeably different results just based on how you measure it (figure 36/37).  I've seen this mentioned in a few different places when trying to measure a fast signal.  Also, I wonder how much the layout is a factor.  What happens if you put a bypass capacitor very close to the driver chip and put the driver as close to the FET gate pins as possible?  I've also seen it mentioned on the forums somewhere that it helps to have the drains close to the capacitors so that the high current wires don't act as inductors too much.

Also, have you tried different gate resistors besides 10ohm?  I've seen different articles on picking a gate resistor value, but I think that has more to do with hard switching and reducing ringing on the output.


Offline neukyhm

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #9 on: March 14, 2019, 11:30:12 PM »
Thanks for the detailed reply!  I wonder how much of that ringing is really there.  Have you seen this AN?

https://www.onsemi.com/pub/Collateral/AN-9005.pdf.pdf

You can get noticeably different results just based on how you measure it (figure 36/37).  I've seen this mentioned in a few different places when trying to measure a fast signal.  Also, I wonder how much the layout is a factor.  What happens if you put a bypass capacitor very close to the driver chip and put the driver as close to the FET gate pins as possible?  I've also seen it mentioned on the forums somewhere that it helps to have the drains close to the capacitors so that the high current wires don't act as inductors too much.

Also, have you tried different gate resistors besides 10ohm?  I've seen different articles on picking a gate resistor value, but I think that has more to do with hard switching and reducing ringing on the output.
I didn't test other gate resistors, but a higher value will reduce noise. However I'm convinced that most of that noise isn't due to the inductance of the path from mosfet driver to mosfet, I think it's because of switching dead time: if the mosfets are switching but none of them is fully ON, then the current the circuit was consuming makes the 100mH inductor create a voltage peak that seeks for ground. This voltage peak at both drains blocks both diodes as I said before, and this makes the mosfet driver try to turn on both transistors for an instant. But both transistors can't be enabled at the same time because if one of them is, the opposite diode is looking at ground and disables it's mosfet (*) This keeps happening for a few nanoseconds until the voltage peak of the 100mH disappears and everything goes back to normal oscillating, that's my hypothesis.

(*) Omg this is so hard to explain

Offline PowerTech

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #10 on: December 25, 2022, 09:09:28 AM »
Hi, I'm building this improved ZVS to achieve 1.5kW power output at 30-40kHz, 60V DC input voltage, with 2xIRFP250 in parallel.
To improve mosfet protection I added TVS 1.5KE200CA to drain-source
Also I want add a 15V TVS, to protect driver inputs, connecting it to ground and in between UF4007 and 100R resistor connection point, this worth it ?

Offline AstRii

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #11 on: December 25, 2022, 09:23:18 AM »
To improve mosfet protection I added TVS 1.5KE200CA to drain-source

I'm against the use of TVS across Drain-Source or Collector-Emitter of transistors. It may seem like TVS diode is the ultimate solution to overshoots but in my experience it's not. There are also others on this forum with the exact same issue with TVS diodes.. The thing is that TVS diodes absorb all the energy of the voltage transient which can be *a lot* of energy. This can lead to destruction of the TVS diode which often ends up as a short circuit. If one of the TVS fails short, you will have a short circuit each time the opposing transistors switches on, which will destroy it sooner or later. This happened to me in my first Tesla coil build.

Using TVS on the Gates is a different story, that's perfectly fine in my opinion. Even if the GDT somehow dumps all it's energy from the core to the Gate TVS diode, it's not that much energy and the diode will most likely survive. The potentially harmful energy flowing in the output of a power inverter is much higher especially in resonant topologies.

Much better solution to damp the Drain-Source transients is to use RC snubbers. Have a look at the scope to see at which frequency does your transients occur. Then design an RC filter with a cut-off frequency lower than the frequency of the transients, and the spikes should be (mostly) gone.
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Offline PowerTech

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #12 on: December 25, 2022, 09:50:47 AM »
Thanks for the information, I will take it into account.
I used TVS across D-S in classic Mazilli driver, no issues so far, at maximum input power 1kW.
Also if using soft start, these spikes will be with lower amplitude and don't reach TVS trip value.
The main source of spikes is the moments when arc breaks, I think so.
As soft start I mean to start with low power 12V power supply, then power on main psu.

Update: got magic smoke from driver chip, transformer secondary was no load(no arc) at burnout time.
Driver power supply is chinese 12V 2A psu, main power is 24V 10A, powered on several times with arc for approx. 3 seconds - all ok, then power on with no arc = fail after 5 sec.
I think here is 2 fail scenarios:
 1) Driver overload - i use 2xIRFP250, so 2x10R(5R eqivalent) resistor on each may result to large current.
 2) Spike to driver - burnout due overvoltage on inputs(1IN1, 2IN1)

Later i add 12V TVS to TPS2814P inputs, and if it fails again - revert to default Mazilli driver, that is stable even with dirty build(long wires everywhere).
« Last Edit: December 25, 2022, 03:41:56 PM by PowerTech »

Offline davekni

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #13 on: December 25, 2022, 07:50:27 PM »
Quote
Later i add 12V TVS to TPS2814P inputs, and if it fails again - revert to default Mazilli driver, that is stable even with dirty build(long wires everywhere).
This TPS2814P circuit appears to have been tweaked to work under specific conditions.  It would not work over the worst-case guaranteed specifications of the driver chip (high or low end of input threshold).  I'd recommend against copying it.  Somewhere on this forum I'd seen another ZVS circuit using a gate driver chip that was better.

The following thread may be useful.  It's about shifting gate voltage on a conventional ZVS oscillator to fix the issue of off-state Vgs getting too high:
https://highvoltageforum.net/index.php?topic=2226.msg16607#msg16607

Another option that helps a bit is to use small FETs instead of diodes to connect drain voltage to opposite FET's gate.  Reduces off-state gate voltage by one diode forward drop.  This example uses IGBTs as the main switches instead of large FETs, but the idea works just as well for FETs:
https://highvoltageforum.net/index.php?topic=831.msg5491#msg5491
David Knierim

Offline jpsmith123

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #14 on: December 26, 2022, 12:58:36 AM »
I don't have very much experience with Mazzilli ZVS driver circuits yet (I'm waiting to get a few more parts and fooling around with LTspice simulations in the meantime) but in looking at MOSFET data sheets, wouldn't the use of some of the newer MOSFETS  (e.g. IXFH90N20X3 instead of parallel IRFP250N or IRFP260N) obviate the need for fast-gate-drive modifications to the classic circuit - for power levels up to a few kW at least, or am I missing something?

Offline davekni

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #15 on: December 26, 2022, 03:27:20 AM »
Quote
IXFH90N20X3
Wow, that is quite a FET!  Looks like it would replace four parallel IRFP250 parts (or perhaps six-eight of the Chinese counterfeit IRFP250s) with under 1/4th gate charge.  Would allow high power without excessively low gate pull-up resistor values.  BTW, using a lower voltage for gate pull-up resistors has two advantages.  Reduces resistor power for given gate current, and allows gate voltage supply to be turned on before main drain supply.  That fixes startup issues.

Another option to consider is fast IGBTs.  They have higher gate threshold voltage than FETs and lower Vce than FETs at high current.  Of course, they do have their own quirk of slower turn-on and especially turn-off.  That's why I had to add 2.8ohm series resistors to gate drive in my IGBT version:
https://highvoltageforum.net/index.php?topic=831.msg5491#msg5491
Slow forward recovery time of IGBT internal anti-parallel diodes allows Vce to reverse several volts.  If designing this again, I'd probably change D2 and D3 to bidirectional TVS diodes instead of 1N5819.  Vce spike is probably within IGBT negative gate voltage limits.  Standard diode-coupled ZVS circuit should work with IGBTs as well, though I haven't built any other IGBT versions than the above link.

Quote
I used TVS across D-S in classic Mazilli driver, no issues so far, at maximum input power 1kW.
Also if using soft start, these spikes will be with lower amplitude and don't reach TVS trip value.
The main source of spikes is the moments when arc breaks, I think so.
As soft start I mean to start with low power 12V power supply, then power on main psu.
Soft-start of gate-supply first is the ideal solution to startup issues.  With startup fixed, yes, arc breaking is the remaining issue as I found in above Jacob's ladder link.  Just before arc breaking is maximum power draw, so maximum current in inductors coupling supply to FET drains.  When arc breaks, power drops to almost zero.  All the energy stored in those inductors dumps into the resonant circuit, making voltage spike.  "Spike" rise time is multiple cycles, so not what people typically call a "spike".  If you know peak input current and inductance, calculate the stored energy.  Either the FETs or added TVS diodes need to dissipate that energy.  I had to use an array of TVS diodes to handle the energy in my circuit.  (Input power hits 3kW-4kW before arc breaks, even though average power is about 1kW.)  Clamping issues are quite different in these ZVS oscillators compared to H-bridges due to the "spike" duration being orders-of-magnitude longer.

One other caution in using ZVS oscillator for driving a transformer into arc:  Make sure transformer coupling factor is 0.85 or lower.  Otherwise at just the wrong arc load resistance, resonant Q gets too low to sustain oscillation, causing current to ramp up indefinitely.
« Last Edit: December 26, 2022, 03:35:52 AM by davekni »
David Knierim

Offline PowerTech

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #16 on: December 26, 2022, 09:28:50 AM »
Thank U for the useful information.
To calculate "spike" energy I found this -
 

E=(1 / 2) * ((100 / 1000000) * 30^2) * (60 / (60 - 50))
E=0.27J
For IRFP250N  single pulse avalanche energy is 315mJ, so no issue to handle this energy, if I calculated correctly.
Inductor stored energy with 100uH/30A is only 0.045J
« Last Edit: December 26, 2022, 09:40:47 AM by PowerTech »

Offline davekni

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #17 on: December 26, 2022, 07:41:51 PM »
Quote
To calculate "spike" energy I found this -
Yes, that is more accurate than looking at just inductor stored energy.  That final factor of (BVds / (BVds - Vdd)) accounts for additional energy from power supply voltage Vdd during avalanche breakdown event.

Quote
E=(1 / 2) * ((100 / 1000000) * 30^2) * (60 / (60 - 50))
E=0.27J
For IRFP250N  single pulse avalanche energy is 315mJ, so no issue to handle this energy, if I calculated correctly.
Inductor stored energy with 100uH/30A is only 0.045J
Yes, you'll probably be fine.  There are many considerations that complicate the actual situation compared to simple formula.  Most reduce actual avalanche energy, so will help further.  One important consideration that goes the other way:  Is the current really 30A at the point arc breaks?  I'd designed mine for 1kW.  Average power is roughly 1kW.  However, at arc break, power is several times higher (current several times higher).
Also, 315mJ specification is for initial die temperature of 25C.  In real operation, initial temperature is higher, so avalanche capability lower.
        Considerations that reduce energy:
1) Inductor saturation reduces inductance at high current.
2) Energy is shared by multiple FETs.
3) Actual FET BVds is likely higher than 200V, especially as die heats up.  Equivalent DC breakdown voltage for ZVS oscillator is 200/PI = 63.66V or higher for typical parts.
4) Losses in resonant circuit and inductor resistance absorb some of the energy that would otherwise go to avalanche breakdown.
David Knierim

Offline PowerTech

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #18 on: December 27, 2022, 05:17:43 PM »
Quote
Is the current really 30A at the point arc breaks?
For more precise value I need measure it with oscilloscope, I will do it later.
Quote
One other caution in using ZVS oscillator for driving a transformer into arc:  Make sure transformer coupling factor is 0.85 or lower.  Otherwise at just the wrong arc load resistance, resonant Q gets too low to sustain oscillation, causing current to ramp up indefinitely.
I want use copper foil for primary winding, primary and secondary is on different ferrite leg sides, this can cause coupling factor rise > 0.85 ?

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #19 on: December 27, 2022, 07:52:07 PM »
Quote
I want use copper foil for primary winding, primary and secondary is on different ferrite leg sides, this can cause coupling factor rise > 0.85?
Foil will reduce coupling a bit compared to wire.  With primary and secondary on different legs, likely still below 0.85.  Measurement is the only way to know for sure.
One simple way to measure coupling factor is to measure oscillation frequency with secondary open and again with secondary shorted.  Probably best to do this at low power (low DC input voltage) to avoid issues of arcs during open-secondary test.  If shorted oscillation frequency is more than 1.9x open frequency, then coupling is too high.  (If I recall correctly, my Jacob's ladder ZVS runs 1.86x frequency with shorted secondary.  Close to maximum coupling gives best performance.)
For the math, I'll use K for coupling factor, Lo for primary inductance with open secondary, Ls for primary leakage inductance (secondary shorted), Fo and Fs for open and shorted frequencies respectively, and C for resonant capacitance.
    Fo = 1 / (2 * PI * sqrt(Lo * C));
    Fs = 1 / (2 * PI * sqrt(Ls * C));
    Ls = Lo * (1 - K * K);  Implies that  Lo / Ls = 1 / (1 - K * K);
    Fs / Fo = sqrt(Lo / Ls) = sqrt(1 / (1 - K * K));
For K = 0.85, Fs / Fo = sqrt(1 / (1 - K * K)) = sqrt(1 / 0.2775) = sqrt(3.604) = 1.9;

BTW, the coupling limit of 0.85 is from experiments and LTSpice simulation, not from any math formula I'm aware of.  From simulation, precise threshold was 0.86, but I use 0.85 to have a tiny bit of margin.  Experiments matched simulation quite well.

Perhaps more details than you wanted :)
David Knierim

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Re: Piernas's Fast ZVS Mazzilli Driver
« Reply #19 on: December 27, 2022, 07:52:07 PM »

 


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March 26, 2024, 03:16:03 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
Anders Mikkelsen
March 26, 2024, 01:41:49 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 26, 2024, 04:48:22 AM
post Re: Re-chargeable 1.5 volt lithium ion AAA batteries
[General Chat]
MRMILSTAR
March 26, 2024, 04:16:37 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 26, 2024, 04:16:24 AM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
davekni
March 26, 2024, 04:13:02 AM
post Re: CM400 Induction Heater
[Electronic Circuits]
davekni
March 26, 2024, 04:00:43 AM
post Re: Re-chargeable 1.5 volt lithium ion AAA batteries
[General Chat]
davekni
March 26, 2024, 03:19:18 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
thedoc298
March 26, 2024, 01:50:42 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 25, 2024, 08:05:02 PM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
Mads Barnkob
March 25, 2024, 07:41:29 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 25, 2024, 06:45:46 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 25, 2024, 05:44:25 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
Anders Mikkelsen
March 25, 2024, 04:47:17 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 25, 2024, 04:27:22 PM
post Re-chargeable 1.5 volt lithium ion AAA batteries
[General Chat]
MRMILSTAR
March 25, 2024, 03:57:34 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
markus
March 25, 2024, 02:06:41 PM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
KrisPringle
March 25, 2024, 04:43:25 AM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
davekni
March 25, 2024, 02:39:40 AM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
KrisPringle
March 25, 2024, 12:47:09 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 24, 2024, 07:36:32 PM
post Re: My completed 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
Alberto
March 24, 2024, 07:27:24 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 24, 2024, 04:25:23 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 10:47:35 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 09:30:21 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 04:34:31 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 03:04:25 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 01:38:34 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 04:20:03 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
davekni
March 23, 2024, 12:54:30 AM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
davekni
March 23, 2024, 12:05:57 AM
post capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 22, 2024, 11:45:03 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
OmGigaTron
March 22, 2024, 11:30:09 PM
post Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
Mads Barnkob
March 22, 2024, 10:20:35 PM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Benbmw
March 22, 2024, 09:21:13 PM
post Re: What actually kills MOSFETs?
[Beginners]
AstRii
March 22, 2024, 03:37:11 PM
post What actually kills MOSFETs?
[Beginners]
FPS
March 22, 2024, 05:09:20 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 22, 2024, 03:57:54 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 22, 2024, 02:59:25 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 21, 2024, 06:31:42 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
rikkitikkitavi
March 21, 2024, 03:08:01 PM
post Re: [WTS] IGBT, Ferrite, Capacitors, Tools, PSU, Industrial components and parts
[Sell / Buy / Trade]
Mads Barnkob
March 21, 2024, 01:37:32 PM
post Re: Difference between these transformers
[Transformer (Ferrite Core)]
Alberto
March 21, 2024, 11:42:07 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 21, 2024, 04:09:14 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 21, 2024, 02:15:31 AM
post My Homemade Structural Analysis X-Ray Machine
[X-ray]
Luca c.
March 21, 2024, 01:35:40 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
March 20, 2024, 10:40:00 PM
post Re: Difference between these transformers
[Transformer (Ferrite Core)]
Mads Barnkob
March 20, 2024, 08:03:41 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Mads Barnkob
March 20, 2024, 07:51:57 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 20, 2024, 10:39:47 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 20, 2024, 04:09:59 AM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 20, 2024, 01:13:23 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Keybored
March 20, 2024, 12:45:16 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 20, 2024, 12:30:30 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 19, 2024, 11:12:24 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 19, 2024, 09:47:49 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 19, 2024, 09:44:19 PM
post Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
March 19, 2024, 06:52:09 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 19, 2024, 05:02:44 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
Mads Barnkob
March 19, 2024, 05:01:41 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 19, 2024, 04:31:02 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 19, 2024, 03:59:54 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 19, 2024, 06:41:39 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
davekni
March 19, 2024, 04:05:49 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
OmGigaTron
March 18, 2024, 09:08:35 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
2020-Man
March 18, 2024, 09:07:35 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
Twospoons
March 18, 2024, 08:57:06 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
MRMILSTAR
March 18, 2024, 03:51:33 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 18, 2024, 02:59:46 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 18, 2024, 02:33:25 PM
post Can I Trust This Super Cheap Site?
[General Chat]
2020-Man
March 18, 2024, 11:02:12 AM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Twospoons
March 18, 2024, 02:36:11 AM
post Re: Best forum for vacuum tube amplifiers?
[General Chat]
Mads Barnkob
March 17, 2024, 07:42:55 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 04:15:14 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 05:05:04 AM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
davekni
March 17, 2024, 04:50:51 AM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Twospoons
March 17, 2024, 04:45:17 AM
post 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 04:17:51 AM
post Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Terry
March 17, 2024, 01:29:32 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 17, 2024, 12:33:06 AM

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