Author Topic: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]  (Read 625 times)

Offline TiagoBS

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Hey guys, at the beginning of the year I finished my first half bridge sstc. The result was amazing thanks to your help!

Now I'm looking for a new project and I came across this video:

https://youtu.be/DpM4hGyOrm4


The proposed circuit is this one, much seen and used on the internet. However unlike the ones seen on the internet (eg Labcoatz Single Mosfet SSTC) it does not use a ballast.


I also found interesting the interrupter he implemented from a relay and an arduino. He also showed how the use of an adjustable voltage regulator affects the output format.


40cm sword sparks! I found this result very intriguing and impressive.

Well, driverless sstc with this circuit doesn't seem that complex to build (wrong  :-\), so I decided to build and see.

I used the same circuit proposed by him (without the snubber), but instead of using an Arduino I used a lm358 board with a 555 to trigger the relay.

Now comes my problem. I'm also not using a ballast and my circuit barely worked with 27vdc 15A from a power source, with that input voltage there was no output on the coil, but the coil lit a fluorescent lamp at close range.
The coil didn't work at 120vac, when I tried to use that voltage I blew the 5A fuse and damage my Mosfet.

Here is some pictures of my circuit and the respective component values.

In gray the Snubber that I'm thinking of using as I couldn't measure the inductance of the primary coil to calculate the ideal value.



The secondary coil has a frequency of 726kHz according to JavaTc. Approximately 650 turns of 32 awg wire. 150mm in length in a 75mm diameter PVC pipe. The primary coil has 4 turns and the Coupling Coefficient stood at 0.359.


BTW. I now have a cheap oscilloscope which should be enough to get some information about the circuit's operation and troubleshooting!
I just need to learn where to take measurements.  :D
When measuring the voltage divider with the potentiometer at 50k the oscilloscope showed 9.8v at 120vac.

Some guides I'm using:
Labcoatz single mosfet sstc
https://www.instructables.com/Simplest-POWERFUL-Solid-State-Tesla-Coil-SSTC/
And the teslista555 guide for single mosfet sstc with 31vdc input.
https://www.vn-experimenty.eu/teslov-transformator/sstc/mini-sstc.html

Questions:
Does it make sense to implement this type of interrupter?
Is it possible for this circuit to work at 120vac without a ballast?
Should the snubber be used together with 400v tvs?
Are the values ​​of the components used by me close enough?
How do I know if my Mosfet is suitable for the secondary frequency?(always wanted to know this)
What can I improve on my circuit for more reliable operation?(as soon as it works!)
How to measure primary coil inductance?
(I tried using an LCR Meter but it identified the primary as a resistor, is it possible to use a function generator for this?)

Thanks to everyone who can share knowledge and help!
« Last Edit: August 19, 2022, 09:34:50 PM by TiagoBS »

Offline davekni

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Quote
Well, driverless sstc with this circuit doesn't seem that complex to build (wrong  :-\), so I decided to build and see.
Yes, these class-E circuits are simple in the sense of low part count.  Class-E Tesla coils also tend to be quite finicky.  If not precisely tuned, fried FET (or IGBT in this case) is common.  Most people build these because they look simple.  With lots of trial and error, some manage good results after some number of fried parts being replaced.
Such simple designs can also be a great learning project, especially when paired with a scope and analog simulation (ie. LTSpice or other).  Get simulated and scope waveforms to roughly match at low voltage (where parts are less likely to fry) before increasing voltage & power.
Inductance of lead wires can be significant.  Your build is better in that respect, shorter wires and paired (twisted or ran side-by-side such as to primary coil).

Quote
Does it make sense to implement this type of interrupter?
Simple.  Mechanical relay will have limited life, in case that matters.  Notice varying behavior in video based on when relay closes relative to line voltage (phase).

Quote
Is it possible for this circuit to work at 120vac without a ballast?
Yes, class-E oscillators can work without ballast.  Ballast can reduce failures due to mis-tuning, but also limits output power.

Quote
Should the snubber be used together with 400v tvs?
The "snubber" circuit in the video is really the primary tuning capacitor.  Notice that resistor is removed in that version.  Some class-E circuits use only "parasitic" drain capacitance, but most need additional capacitance to properly tune primary.

Quote
Are the values ​​of the components used by me close enough?
Analog simulation (LTSpice or ...) is the way to tell.

Quote
How do I know if my Mosfet is suitable for the secondary frequency?(always wanted to know this)
Power and voltage rating are more likely limiting than frequency here.  Counterfeit IRFP460s are very common, often with ~1/2 power capability of genuine parts.  Also note that the video shows changing to a 1200V IGBT with much higher power capability.  Depends on performance you want to achieve.

Quote
What can I improve on my circuit for more reliable operation?(as soon as it works!)
Simulate and measure.

Quote
How to measure primary coil inductance?
JavaTC is likely more accurate than any cheap meter.  If you want to measure, place a known capacitance in parallel and measure resonant frequency (w/o secondary).

Good luck with your project!
« Last Edit: August 20, 2022, 02:25:17 AM by davekni »
David Knierim

Offline TiagoBS

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Hey, guys
I did some tests and modifications in the circuit and managed to make it work with an interesting output.
I'm using a 27vdc 15A power supply.


I added a 1nF capacitor and a 22Ω resistor between DS (although I have calculated, with a little doubt, to avoid the spikes above 100v a resistor capacitor set of 8nF and 13Ω). I haven't measured the difference this might have made yet as I was unsure if I can use my oscilloscope probe to measure it (10:1 probe: 800Vpp (±400V)).
I also reduced the primary coil to two turns. I believe this change was the one that had the biggest impact.
For the next tests I'm thinking of using just one turn, but I'm uncertain if the low impedance could cause problems.

I also did simulations in LTspice and EasyEDA, but I'm having a hard time finding equivalent components like MOSFETs, however I was able to simulate the voltage divider and see the waveforms.

The interrupter works with a relay cutting the power supply voltage. The relay is being operated by an lm358 board.
Here I have already identified two problems. First is that when cutting the main voltage the relay is getting stuck on sometimes. The second problem is that the lm358 output is 5v and the relay uses 12v and this is preventing the relay from working properly.
During the tests, including in the gif, there were times when the relay worked fast enough to cause the switch effect on the output.

I'm going to change the circuit to interrupt the signal going to the Mosfet's Gate instead of the main voltage. I believe that this is the correct way and that I should have done it from the beginning.
To get around the problem of the malfunctioning relay I will try to use an L298N to activate it with 12v.

I intend to implement a switch using a 555, but I'm enjoying implementing one thing at a time, even if in a more archaic way because I'm starting to understand things better.
I'm also tending to use 30vdc on this coil instead of 120ac. A low voltage interrupted coil looks nice, maybe an irfz44n half bridge in the future.

Questions:
-Is there a relationship between the secondary diameter and the input voltage? For example, my secondary is 75mm in diameter, for a coil running at low voltage, would a smaller diameter coil be better?
-Would it be possible to use the lm358 to operate the Mosfet Gate directly? (Or maybe the GDT?)


This is the circuit of a low voltage coil proposed by Teslista555. I found it very interesting and I was left with a few questions:
-Why two diodes d1 and d3?
-Why was a resistor R3 used before the Gate?
-C2 is a resonant capacitor?
-Why is the circuit connected to the ground?

Thanks in advance for the help!
« Last Edit: August 30, 2022, 03:18:56 AM by TiagoBS »

Offline davekni

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Quote
-Why two diodes d1 and d3?
Presume "d1 and d2".  Probably because he didn't have single diodes rated for high enough current.

Quote
-Why was a resistor R3 used before the Gate?
To adjust gate voltage so that FET draws just enough current to start oscillation, but not enough to burn out.

Quote
-C2 is a resonant capacitor?
Yes.  Primary resonant current flows through C1 as well, so both C1 and C2 need to be capable of handling primary resonant current.

Quote
-Why is the circuit connected to the ground?
Because secondary current needs to return to ground.  Most of the top-load capacitance is to ground.  Bottom needs to return to ground to complete secondary resonant circuit.

Not sure I understand the other questions.
« Last Edit: August 30, 2022, 06:04:13 AM by davekni »
David Knierim

Offline davekni

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Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
« Reply #4 on: September 03, 2022, 06:16:12 AM »
Quote
I also did simulations in LTspice and EasyEDA, but I'm having a hard time finding equivalent components like MOSFETs, however I was able to simulate the voltage divider and see the waveforms.
Try a free program called "LTSpice_MOStool.exe".  I use it both at home and work.  Enter data-sheet parameters and it generates an LTSpice VDmos model.  A number of the parameters will require reading from data-sheet graphs, such as capacitances at different voltages and diode forward drop at different currents.  Fourth file down in this link is the executable to download:
https://groups.io/g/LTspice/files/z_yahoo/Util/Model%20Tools/Board%20Level%20MOSFET%20%28VDmos%29/Software

David Knierim

Offline TiagoBS

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Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
« Reply #5 on: September 20, 2022, 06:23:54 PM »
Hey, guys!
Updates:
I'm learning a lot with this new project, every time I make a change I have a lot of questions.

The changes I made were as follows:



I added a 10k resistor before the Gate, changed the Snubber to 15nF 10ohm and primary with 2 turns.

I tested several combinations and also tested some calculations (I'm basing it on Java TC's primary coil inductance value) and came to some conclusions (Although not sure). The capacitance needed to limit voltage spikes increases 4 times when the desired voltage is divided by 2. For example, by limiting the spikes to 180v my calculations showed a value of 2.4nF. Reducing from 180v to 90v the required capacitance is 9.8nF.
I'm just using these calculations as an estimate of values ​​because I'm not sure about the values ​​of the variables used.
[This conclusion may be too clear for more experienced coilers, but I'm learning on the fly in this project  :D]

In the tests performed I used 120vac mains voltage with a ballast instead of 27vdc as I was using.


I noticed that the output seems to be weaker, with thiner discharges.

As I am interrupting the circuit from a relay commanded by a 555 circuit I tried to use a 1000uF capacitor after the diode. In conjunction with this change I also started to interrupt the voltage going to the Mosfet Gate instead of the mains voltage. However, when doing this, the output was very weak, almost non-existent. I also noticed that with this change the coil now seems to work continuously with stronger pulses when the relay is activated (When a lamp is close, it remains lit and pulses with stronger luminosity when the relay is activated).

Questions:
I tried to add one more lamp in series with the one I used as a ballast and I didn't notice any difference in the result. Shouldn't the circuit show a difference in the output?

Can I wind up a transformer and use it as a ballast?
What measurements determine ballast in relation to output power? (Amps consumed in operation by ballast?)

Quote
I also did simulations in LTspice and EasyEDA, but I'm having a hard time finding equivalent components like MOSFETs, however I was able to simulate the voltage divider and see the waveforms.
Try a free program called "LTSpice_MOStool.exe".  I use it both at home and work.  Enter data-sheet parameters and it generates an LTSpice VDmos model.  A number of the parameters will require reading from data-sheet graphs, such as capacitances at different voltages and diode forward drop at different currents.  Fourth file down in this link is the executable to download:
https://groups.io/g/LTspice/files/z_yahoo/Util/Model%20Tools/Board%20Level%20MOSFET%20%28VDmos%29/Software

Thank you very much for the tip, I will test this software!

Offline davekni

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Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
« Reply #6 on: September 21, 2022, 05:50:15 AM »
Quote
I added a 10k resistor before the Gate, changed the Snubber to 15nF 10ohm and primary with 2 turns.
10k gate resistor completely changes circuit operation.  Provides DC gate voltage, but no significant AC current flows through 10k.  The AC component of gate waveform is now only from gate-drain capacitance.  Thus feedback is from primary voltage, not secondary.
10ohm resistor in snubber circuit will dissipate most of the circuits power, leaving little for the coil.  As I said previously, class-E coils want a resonant capacitor here, not a snubber.  Best with no resistance.  Snubbers have uses.  This is the wrong circuit to use a snubber (R + C).

Quote
The capacitance needed to limit voltage spikes increases 4 times when the desired voltage is divided by 2. For example, by limiting the spikes to 180v my calculations showed a value of 2.4nF. Reducing from 180v to 90v the required capacitance is 9.8nF.
This is accurate, at least for one of the most common uses of snubbers.  That is for transformer coupled boost converters (non-resonant flyback converters).  Transformer leakage inductance is constant, as is max load current (current through leakage inductance).  To reduce spike voltage to 1/2 impedance must drop to 1/2.  For fixed inductance, this requires frequency to be 1/2 (spike width to double), requiring 4x capacitance.

Another way to look at class-E circuits such as this:  The drain (collector) waveform consists of only relatively-wide "spikes" that form the resonant waveform.  These "spikes" are the top part of a sine-wave.  The remainder of the sine wave is clamped to ~0V by FET/IGBT conduction.  If the "spike" voltage is too high, then the resonant capacitor (the drain-source or collector-emitter capacitor) needs to be increased to widen the "spike" and thus lower its peak voltage.  Or, operating current needs to be reduced to reduce spike voltage.

Quote
Can I wind up a transformer and use it as a ballast?
What you want to wind is an inductor, not a transformer.  A transformer core can be used, but an air gap should be added into the magnetic path.

Quote
What measurements determine ballast in relation to output power? (Amps consumed in operation by ballast?)
Simulation is a good way to experiment.  Use an inductor as ballast and try different inductance values.

Have fun learning!
David Knierim

Offline TiagoBS

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Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
« Reply #7 on: September 29, 2022, 10:23:27 PM »
Good news!


-


I'm finally getting to an interesting result with this circuit!

I replaced the electromechanical relay with a solid state relay, and using 120vac with an adjustable voltage regulator I was able to change the shape and intensity of the discharges. Sword shape discharges with muffled sound!


When I'm measuring DS with my oscilloscope I'm not able to use the trigger function correctly I think, but I was able to identify times when the vmax was 198v (the top part of a sine-wave?).

Another way to look at class-E circuits such as this:  The drain (collector) waveform consists of only relatively-wide "spikes" that form the resonant waveform.  These "spikes" are the top part of a sine-wave.  The remainder of the sine wave is clamped to ~0V by FET/IGBT conduction.  If the "spike" voltage is too high, then the resonant capacitor (the drain-source or collector-emitter capacitor) needs to be increased to widen the "spike" and thus lower its peak voltage.  Or, operating current needs to be reduced to reduce spike voltage.

I will test larger capacitor values between DS. But I need to figure out a way to be able to see the still waveform on the oscilloscope screen.

By accident I discovered that the circuit is working without the ballast. In one of the tests, with a new transistor of a different brand I forgot to connect the ballast and the circuit worked at full mains power!
Although I haven't done more tests or used the relay to interrupt the signal because I think I have to optimize the values ​​of all components before that.

I also changed the primary from 2 to 3 turns and this greatly increased the size of the output, at the moment using 2 100w lamps in parallel I'm getting 10-11cm discharges.

Now I believe the next step would be to optimize the capacitor between DS.

Questions:
Why increasing the number of turns on the primary from 2 to 3 did the output increase and why increasing the height of the primary does the opposite?
I'm using two 100w lamps in parallel as a ballast, how do I calculate the value of an equivalent inductor?
For the solid state relay to work I had to connect a lamp to its output, along with the sstc circuit, is there any alternative to this problem?
So that I don't have to leave a light bulb plugged into it.

Offline davekni

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Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
« Reply #8 on: September 30, 2022, 05:01:14 AM »
Quote
I will test larger capacitor values between DS. But I need to figure out a way to be able to see the still waveform on the oscilloscope screen.
Looks like you have a digital oscilloscope.  It likely has an acquisition mode for single-capture.  That mode stops acquisition after the first trigger event it sees.  Result will be stable.  Manually (scope menu/buttons) enable acquisition to make the next capture.

Quote
Why increasing the number of turns on the primary from 2 to 3 did the output increase and why increasing the height of the primary does the opposite
For my class-E coils (6.78MHz and 13.58MHz), required iterations of simulation and scope measurement to figure out optimum values.

Quote
I'm using two 100w lamps in parallel as a ballast, how do I calculate the value of an equivalent inductor?
No exact answer.  Incandescent lamp resistance changes about 15:1 between cold and hot (full voltage to lamp).  Exact resistance for your use is unknown, and changing some even during your half-cycles of enable.  First order:  Start with nominal lamp resistance at full power.  Calculate inductance that has same impedance as lamp at your line frequency (50 or 60Hz).  Use that inductance.

Quote
For the solid state relay to work I had to connect a lamp to its output, along with the sstc circuit, is there any alternative to this problem?
AC SSRs (solid state relays) generally use TRIACs internally, with gate pulses shortly after line voltage zero-crossings.  TRIACs need load current to remain enabled for the remainder of each line half-cycle.  Your class-E circuit must not be drawing sufficient current initially to keep TRIAC enabled.  I've used lamps for this purpose too.  Depending on the SSR, a small lamp of 5-10W may be sufficient.
David Knierim

Offline TiagoBS

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I added two more lamps in parallel, making a total of 4.
The result is already beyond what I could have expected!



I used a FGA60N65SMD in place of the IRFP460.
With that inductance as a ballast I was able to use the adjustable voltage regulator and get swords like sparks.


I was also able to connect the circuit to the mains voltage without ballasts and use the interrupter. However, the IGBT burned out when I tried to go to the limit of the adjustable voltage regulator (that was possible using the 4 lamps as ballast).
The last spark.




Some changes I will make:
Add a new toroid.
Increase the primary coil from 3 to 4 turns.
Perhaps further increase the capacitance of C between Collector and Emitter*.
I will also redo the entire circuit in a smaller package to reduce unwanted inductance.

Questions:
The first one is related to the capacitance between Collector and Emitter.

Here is the data related to my primary and secondary set.



I don't know if I'm doing the calculations correctly.
My secondary's frequency is around 649kHz and the primary's inductance is around 1,387 microhenry. I believe that the capacitance value to be considered is in relation to the capacitor between Collector and Emitter, right?
So, using a higher value for C would be bringing the primary impedance down, in this case, when using 68nF the impedance would be close to 2ohms, which I believe is bad for the IGBT, right?
Is there any way to calculate the primary impedance "ideal" range in relation to the IGBT/MOSFET used, or is it just from experimentation?

Second question.
I don't intend to use a bunch of light bulbs in my circuit. So I'm looking for an inductor to replace the bulbs.
So I performed the measurement as suggested to have a reference of an inductor that would give me an approximate result.

Quote
I'm using two 100w lamps in parallel as a ballast, how do I calculate the value of an equivalent inductor?
No exact answer.  Incandescent lamp resistance changes about 15:1 between cold and hot (full voltage to lamp).  Exact resistance for your use is unknown, and changing some even during your half-cycles of enable.  First order:  Start with nominal lamp resistance at full power.  Calculate inductance that has same impedance as lamp at your line frequency (50 or 60Hz).  Use that inductance.


And from the Inductor Impedance formula (XL= 2πfL) from this post:
https://highvoltageforum.net/index.php?topic=1739.0
I got the following result:

Current of the lamps in AC and DC

4 lamps in AC - 3.2A
4 lamps in DC (Rectified with 1 diode 10A10) - 1.7A

Z = U/I
Z= 120V / 3.2A (Current of 4 lamps in parallel)
Z= 37.5 Ohms

Inductor Impedance
Zl = 2*PI*f*L

L = Zl/(2*PI*f)
L = 37.5 Ohms / (2*3.14*60Hz)
L = 37.5 / 376.8
L = 0.09952229
L = 99.5 millihenry
or
L = 185 millihenry, since the current of the 4 lamps in DC (After a single 10A10 diode) is close to 1.6A.

Are the calculations correct?

Third question:
This was the waveform I was able to measure between Collector and Emitter. I increased the value of C, however I didn't notice a difference in the format or in the maximum voltage value. What is this ringing voltage at the end of the wave?
Is this elevation at the beginning the ramp that allows sword like output?
« Last Edit: Today at 05:35:08 PM by TiagoBS »

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September 28, 2022, 08:28:16 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 28, 2022, 06:05:46 PM
post Re: controlling the negative gate bias voltage of the Gate drive transformer
[Dual Resonant Solid State Tesla coils (DRSSTC)]
prabhatkumar
September 28, 2022, 05:16:13 PM
post Re: DC charging solution
[Spark Gap Tesla Coils (SGTC)]
davekni
September 28, 2022, 05:43:34 AM
post Re: Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
davekni
September 28, 2022, 05:20:55 AM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 28, 2022, 05:15:19 AM
post Re: Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
dru
September 27, 2022, 07:11:42 PM
post Re: Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
dru
September 27, 2022, 07:07:00 PM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
JCF
September 27, 2022, 05:08:45 PM
post DC charging solution
[Spark Gap Tesla Coils (SGTC)]
Conrad73
September 27, 2022, 04:57:38 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 27, 2022, 03:12:49 AM
post Re: Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
klugesmith
September 27, 2022, 02:23:44 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 26, 2022, 07:55:31 PM
post Re: Help with PLL induction heater driver
[Electronic Circuits]
dbach
September 26, 2022, 04:04:11 PM
post Re: What am I missing?!?!?
[Spark Gap Tesla Coils (SGTC)]
davekni
September 26, 2022, 05:13:23 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 26, 2022, 05:10:13 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 26, 2022, 05:03:46 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 26, 2022, 04:33:12 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 26, 2022, 03:01:21 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 26, 2022, 01:30:04 AM
post Re: Help with PLL induction heater driver
[Electronic Circuits]
Anders Mikkelsen
September 25, 2022, 10:57:23 PM
post Re: Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 25, 2022, 09:59:53 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 25, 2022, 09:43:24 PM
post Re: Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
davekni
September 25, 2022, 07:33:57 PM
post Re: Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 25, 2022, 07:06:33 PM
post What am I missing?!?!?
[Spark Gap Tesla Coils (SGTC)]
Conrad73
September 25, 2022, 06:35:43 PM
post Radiometer Copenhagen OSG 42b Oscilloscope Repair, From The 1950'ish
[Laboratories, Equipment and Tools]
Mads Barnkob
September 25, 2022, 03:18:22 PM
post Re: Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Rafft
September 25, 2022, 02:53:30 PM
post Recommended development boards for QCWDRSSTC
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
dru
September 25, 2022, 09:05:37 AM
post Re: Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 25, 2022, 08:29:09 AM
post Re: Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 25, 2022, 05:27:41 AM
post Re: Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
klugesmith
September 25, 2022, 02:12:21 AM
post Ud failure
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
September 25, 2022, 01:50:45 AM
post Re: controlling the negative gate bias voltage of the Gate drive transformer
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 24, 2022, 09:36:58 PM
post Re: Gate drive transformer with negative gate bias voltage
[Dual Resonant Solid State Tesla coils (DRSSTC)]
prabhatkumar
September 24, 2022, 06:56:35 AM
post Re: Gate drive transformer with negative gate bias voltage
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 24, 2022, 06:09:03 AM
post Re: Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
davekni
September 24, 2022, 01:32:08 AM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 23, 2022, 10:55:21 PM
post Re: Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
AstRii
September 23, 2022, 10:39:13 PM
post controlling the negative gate bias voltage of the Gate drive transformer
[Dual Resonant Solid State Tesla coils (DRSSTC)]
prabhatkumar
September 23, 2022, 05:48:17 PM
post Gauss meter for strong magnetic fields
[Laboratories, Equipment and Tools]
Peregrine
September 23, 2022, 02:01:10 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 23, 2022, 03:04:31 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 22, 2022, 04:15:36 PM
post Re: SSTC - PCB design
[Beginners]
Przemekk00
September 22, 2022, 12:39:51 PM
post Re: Possible Leads on Single Photon Camera
[General Chat]
alan sailer
September 22, 2022, 12:05:55 AM
post Re: Possible Leads on Single Photon Camera
[General Chat]
Mads Barnkob
September 21, 2022, 10:32:29 PM
post Possible Leads on Single Photon Camera
[General Chat]
alan sailer
September 21, 2022, 03:57:38 PM
post Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
[Solid State Tesla Coils (SSTC)]
davekni
September 21, 2022, 05:50:15 AM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 20, 2022, 10:29:41 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
September 20, 2022, 08:24:30 PM
post Re: Driverless Single Mosfet Relay interrupted SSTC? - [All kinds of problems]
[Solid State Tesla Coils (SSTC)]
TiagoBS
September 20, 2022, 06:23:54 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 20, 2022, 05:20:07 AM
post Re: TO247 mounting
[Beginners]
davekni
September 20, 2022, 05:15:35 AM
post Re: MidiStick V2.0: Next gen tesla coil interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
TMaxElectronics
September 19, 2022, 11:43:47 PM
post Re: TO247 mounting
[Beginners]
Weston
September 19, 2022, 09:58:56 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
September 19, 2022, 09:05:35 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 19, 2022, 12:58:35 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 19, 2022, 12:13:46 AM
post Re: MMC capacitor crash
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 19, 2022, 12:09:22 AM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 18, 2022, 11:38:51 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
FonziDaytona
September 18, 2022, 10:41:54 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
davekni
September 18, 2022, 10:31:32 PM
post Re: Musical interrupter problems
[Solid State Tesla Coils (SSTC)]
RoamingD
September 18, 2022, 10:09:33 PM
post Re: UD2.7 dual Purpose Use
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 18, 2022, 09:58:34 PM

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