Reliable and Flexible Switching System

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Chris posted this 30 September 2017

A Reliable and Flexible Switching System is second to none, it is the most important piece of Hardware one could have on your bench!

I was lucky enough to share some data with a friend that had worked on this same concept with one of his friends, Back then, the idea was called the: Quadratron


Funny enough TheOldScientist has done some videos on this:


I have also build a few versions of my own inception of the: Quadratron which is now called IPC-quadra


Version One:


Version Two:



I have another H Bridge I use also, this is not related to the Quadratron. It is a Custom Built, Salvaged from an Old UPS, 3000VA:


I think it is important to not, this is very handy, but its not a necessity, cheaper and easier options exist. EBay has some good options. Variable Frequency and Duty Cycle are the absolute most important.

High Voltage and Current is not necessary.

I personally find a Microcontroller is a good cheap option! Easy to use, Plug and Play if you don't mind the pun! I have built all my own software:


I think if we combined our skills, we as a team could come up with a community based project that is better and cheaper than all options presented!

China could do cheap PCB's, We could build our own software!

We could find a cheap Microcontroller.

Let me know if you're keen to look into this!


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Chris posted this 01 October 2017

For those that are not in the know, a System like this, a Custom, or a Reliable and Flexible Switching System, will allow you to set a Frequency and a Duty Cycle easily and quickly!

The Microcontroller: 


All controlled from your computer or laptop:






All done very easily, a GUI that can be easily customised! Simply scroll your Mouse Wheel and the Frequency or Duty Cycle is changed.

Alas, no good for cooking Sausages!


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Zanzal posted this 04 October 2017

Were you considering a DIY kit, or a retail item to be sold, or a how-to instructable for people to build their own? I'm all for using knowledge to build useful and exciting products. 

If you are looking for ideas: a tiny OLED screen, a few rotary encoders, and an ESP-32S would be a fairly cheap way to go. Simplify the circuitry by using opto-mosfet drivers (FOD3180 for example). The wifi on the ESP-32S means that a web interface could be added with one of the two cores for signal generation. Add a 3D printed case and a 5V wall adapter.

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Chris posted this 04 October 2017

Hi Zanzal, not sure yet.

The Circuit above is not mine to sell, so I will have to come up with something different.

A small plug and play board would be nice, easy for people to get started.

WiFi has trouble with this sort off thing, the work we are doing, there are frequencies that take out the WiFi and the device becomes unresponsive. So, although a good idea, its a bit hard to incorporate.

Yes a oled would be a good idea!


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cd_sharp posted this 06 October 2017

Hi, guys! I also recently have been having an idea to make an H-bridge. Since I have a dual channel function generator able to control the phase difference between the channels, I came up with this idea:

I wish to use it to feed the primary coil in a device similar to Graham Gunderson. I understood that AC is absolutely necessary. Please, let me know any of your thoughts on this!

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Chris posted this 07 October 2017

Hey CD, a good Reliable Switching System is a real handy tool for sure.

I would like to point out, AC and DC both work and both work equally well, but under different circumstances. AC, however, is much better in the Mr Preva Experiment.

In different Systems, the geometry might be quite different, but the basic under laying processes the same.

For example, we have recently covered how the similarity's are very much the same between the MIT of Graham Gunderson and the 30 Watt Lantern of Akula. Although they are quite different in how they get to the end result, they both get to the same end result.

The Some Coils Buck and some Coils DONT Thread covers a huge amount of the reason behind why I am pointing this out.

Graham Gunderson gave us his Timing Cycle, as did Akula, this is where we should be looking, connecting the dots and making the connections to an Excess in Electromagnetic Induction. In other words Asymmetrical Electromagnetic Induction.

  • AC, a Sinusoidal Wave is a continuous gradual Change over Time
  • DC, Square Wave is a sharp, Transient, then with long periods of no change over Time (DC).

But from the early days of the Andrey Melnichenko GLED, Akula 30 Watt Lantern and through to Ruslans Lantern, DC was used.

Graham Gunderson uses AC to get the same end result.

Years ago, I published a schematic: (Circuit and Layout)


With the following waveform: (Scope Shot - Yellow is Current Input - Red is Voltage Output)


Over at "Akula0083 30 Watt Self Running Generator", this was one of my early break throughs. (April 17, 2014) after already knowing about Bucking Coils and how Electromagnetic Induction worked. This was a super important experiment in learning just a little more in my learning curve! Thus the reason I published it!

Why was it a breakthrough? The polarity of the pulsed Coil flips, according to the Dot Notation, thus the Coils then Buck, Energy is then "Generated" as a result of the basic requirements of Faradays Law.

Not a single soul realised this, replicated to see what I was saying... is full of the same simplicity's it was at its inception, circling in unending circles of nothingness...

I hope this makes sense?


cd_sharp posted this 07 October 2017

Hi, Chris! For the moment I gave up on using pulsed DC and two coils setup (GLED lantern style).

Actually I think that I first heard of an H-bridge from you. But this one

is incomplete. I saw that making an H-bridge using my dual channel FG and 4 MOSFETs is not so straight forward. What signals did you use to drive MOSFETs Q1-Q4? I think Q1 and Q4 gates are being fed a signal 180 degrees out of phase with the signal being fed to Q2 and Q3 gates.

Also, to be able to power anything from the output ends we need a current sensing circuit much like Graham Gunderson uses, which I don't think I am able to draw since my background is not related. I will try to use a MOV on the output, like you have shown Naudin did with the MEG, but I doubt the results could be anything near Graham's.

Thanks for all your help!

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Chris posted this 07 October 2017

Hey CD, if I may, and with your already good knowledge on the Akula 30 W Lantern, suggest that this might be a good path to stay on?

Yes, a pseudo schematic, incomplete for simplicity.

With my recent experiments, Some Coils Buck and some Coils DONT, that was leading up to the Lantern anyway! This should help you along the way. Perhaps replicating my experiments, with simple stuff, a few simple coils, look at the effects, and maximise on these effects, this will be very much more productive than building the entire thing and then finding it does not work. The Circuit is secondary, this is only a Signal to the Mosfet...

What's really important is to see and understand the Coil Interactions! As we saw in the Mr Preva Experiment.

What I have shared is nearly there, its the start to the next step, after your excellent Mr Preva Experiments, you will see where I was heading, in the direction I was heading, I hope?

As we know, from the Mr Preva Experiments, we saw Electromagnetic Induction at its most basic, fundamental levels, but it did take a little work.

Does your FG support the Duty Cycle Adjustment? If so, what's the supported duty cycle range?

My H-Bridges are all Microcontroller driven, one has a H-Bridge IC which there are many of them today. I can share my code, but the Microcontrollers are no longer being made.

The goal of this thread was to get everyone to decide on a Microcontroller, Code it, and then look at a hardware solution as I have shown above. But only better.

To answer your questions, Q1-4 were driven by a circuit like was shown above:


I have 4 of them side by side, controlled by a Microcontroller. Q1 and Q3 are on and Q2 and Q3 are off, then this flips, 180 degrees out of phase. You're Right. This creates an Alternating, Direct Current Switching Cycle.



cd_sharp posted this 07 October 2017

Does your FG support the Duty Cycle Adjustment? If so, what's the supported duty cycle range?

Yes, 0.1-99.9%, it's a Feeltech FY3200S FG, not one of the most expensive ones, but neither the cheapest. It has DTC, Phase, Freq Sweep, TTL and other features. It's more than what I needed until now.

Hey CD, if I may, and with your already good knowledge on the Akula 30 W Lantern, suggest that this might be a good path to stay on?


Perhaps replicating my experiments, with simple stuff, a few simple coils, look at the effects, and maximise on these effects

I trust you. Although I saw no first-hand connection between Mr Preva experiment (which I understand) and Akula lantern (which I had no results with, but it's me to blame), if you say there is one then I will read the material again and retry.

Your guidance is enough to convince me on the next steps.

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Chris posted this 08 October 2017

Were getting off topic and should move our conversation to the Akula's 30 W lantern Thread,

Most of the Akula Circuitry is to drive the Mosfet, he uses the Term Transistor. Not Mosfet.

Which is what we are looking at here in this Thread. The optimum and easiest, flexible configuration to produce a wide range of Wave forms.

It is the Interactions in the Coils, and between the Coils that needs attention.



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devesh posted this 10 November 2017

Hallo guys, I'm not absolutely sure to have correctly understood the meaning of this thread...may you please confirm - or negate - my understanding? 

The need is to produce two square wave signals, which have to be exactly the opposite each other; moreover the duty cycle and the frequency have to be variable but the two signals have to be in sync (mirrored on a scope trace). Right?

If this is the point, I have built a very, very stupid circuit using a dual MOSFET, low side, driver: the MCP14E8 ( which has one straight and one inverting output, to be used to drive the gates of two independent MOSFETs so, connecting in parallel the two input pins and feeding them with a common FG (which can be an Arduino Nano or any kind of small microcontroller), we can drive our bucking coils and make all the test we want.

Depending on the work frequency, and the test voltage, one has only to choose the correct switching devices (IGBTs for the working frequencies below 100KHz, MOSFETs if the frequency should be higher) and their maximum operating ranges.

What I see here very important, in my immense ignorance, is the sharpness of the pulses (rise/fall times) and the material used as the common core of the bucking coils (nanoperm, iron powder, nanocrystalline multilayer, Metglas)... I thinks, also, that the inductance of the bucking coils should be different but the wire mass identical. 

Last, the bore (inner hole) of one of the two coil should be huge - say, more than 10/15cm - where the other should be a quarter - say 2/3cm -. The core, accordingly, should not be regular in its shape but bigger on one side and smaller on another side, preferably a toroid. 

 Let me know if the above is what is needed and I will post the stupid schematic which I built months ago on a breadboard.


Chris posted this 10 November 2017

Hi Devesh - The intention is to possesses a Reliable and Flexible Switching System.

  • Adjustable Frequency
  • Adjustable Duty Cycle

The idea is to switch any sort of wave form easily, cheaply and any format, H-Bridge, Half H-Bridge or single Mosfet Driver.

An entirely flexible system for multi purpose experiments.

The H-Bridge is the most efficient switching that one can employ, it is fast becoming the system of choice for many applications.


devesh posted this 10 November 2017

Ah, not specifically related to the bucking coils tests. Understood. You said "any sort of waveform", mmmhhhh... As per my little knowledge switching AC, especially in the high power applications, we have to use back-to-back MOSFETs arrangements or make use of TRIACS: these two alternative components need a different kind of driving strategy so I can't imagine, at the moment, an all-in-one device so flexible which will be able to drive a so wide range of switching components... Maybe the quadratron does exactly this work: I have to study it deeply.

Chris posted this 19 September 2018

My Friends,

For completeness, and for others looking I want to share information from this topic.

I have said it before, my Electronics skills are very average and I only know enough to be Dangerous, for this reason, simplicity is a very important concept! 

Why use a Mosfet Driver:

  • Isolate the Microcontroller from high Voltage high Current sources.
  • Microcontrollers are normally 3.3 to 5 Volts output. This is not enough to reliably switch most Mosfets. Normally in the range of around 3 - 10 volts are required. See datasheet: Gate Threshold Voltage, 3 Volts normally wouldn't turn the Mosfet on correctly.
  • Ensure the Mosfet is turned on and also off correctly.
  • Other reasons also...


For good reliable switching, a Mosfet Driver can be utilised. I have shown above a circuit I have used that a friend shared with me, that used the MCP1403 Integrated Circuit:



Sometimes you might see a home made Mosfet Driver, using a Push Pull Transistor Array, NPN and PNP Pair. I have not had a lot of success with these arrangements, found then a little tricky and found my time spent elsewhere can be a lot more productive. These arrays may look like Akula's Circuits:



Seen above, back to back on the lower negative rail. switching the KT805AM Transistor via the Resistor Capacitor filter Circuit.

A Mosfet Driver is cheap and very simple to implement, I have shown below that only a few minutes can have an operational circuit with only a few components:




Using Microcontrollers that are .NETMF Ported, it is very easy to get a simple PWM Signal:

Microsoft.SPOT.Hardware.PWM MyPWM = new PWM(Cpu.PWMChannel.PWM_4, 2, 0.01, true);

All that's required is to import the Microsoft dll: 

C:\Program Files (x86)\Microsoft .NET Micro Framework\v4.3\Assemblies\le\Microsoft.SPOT.Hardware.PWM.dll

One can then very easily Start the PWM using:


And to Stop the PWM:



Please note: What I have shown above is not necessary to start off! Start with a simple breadboard as I have shown, a $3 Driver and a few resistors. Cheap Simple and easy!

We have a full section for Microcontrollers, and cover a vast range of Microcontroller's. Use the section, ask questions, someone will try to help as soon as possible!

Using a Microcontroller is a HUGE benefit, however there are some speed limitations. Microcontrollers are not Magic Yet!


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John12 posted this 19 September 2018

Hello Chris and group,

Apologies you state the microcontroller can you elaborate on the Make/Model and any other components/accessories, their make and models 


Would old core memory allow this kind of switching old school (yes I am electronics pre newbie) working on it...

Thank you




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Chris posted this 19 September 2018

Hey John12,

I guess it could under the right conditions.

The main topic is the Reliable and Flexible control of either Mosfets or Transistors for the dedicated Inductive Switching. An area lacking for us in the Research Field.


Vidura posted this 20 September 2018

Related to this thread I would like to post some experiences and ideas. I have used custom made pwm generator s with microcontrollers and analogue ic, both have there advantages and drawbacks. Microcontrollers are accurate, can be clocked with crystals, and have very flexible programable adjustments and operating modes, a drawback is the limited resolution of duty cycle and frequency, and a kind of rippeling when scrolling . In contrast the analog ICs have virtually infinite resolution in frequency and duty cycle, although at the cost of less stability and flexibility. A few months ago I decided to purchase a function generator, a useful tool for electronic works, but regarding the pwm-square wave mode I am not at all convinced that it is the best solution. There might be better devices available, but the one I bought is have only one rotary encoder, so for every change of a parameter I have to change the selected mode , the decimal range etc, which is quite impractical.So I prefer the simple pwm with two variable resistors , where I can adjust frequency and duty cycle simultaneously, and sweep throu the range quickly. So I was thinking about how to unify the advantages of the microcontrollers and the analogue IC. I found some microcontrollers with NCO , a numerical controled oscillator, which have an excellent resolution and accuracy, combined with the flexibility of a programmable MC. When I have something elaborate I will post here or in the microcontroller section.

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Chris posted this 20 September 2018

Hey Vidura,

Excellent Post! You taught me something valuable Thank You!

All members have access to the Microcontroller section now. Please let me know if there are any problems accessing or posting.


cd_sharp posted this 3 weeks ago

Hey, guys

This thread is awesome. One can learn so many things even by looking at the first schema on top.

While waiting for the power switches and supply from Vidura, I worked on their powering stage. Here goes:

That on the left is an old ATX supply from a very old PC. I connected the outputs and the on-off switch into an empty box (the black one). I'm using it to power a poor man's switch I built manually.


-Vidura's power module can most likely be powered by an ATX supply with no problem. I can't wait for the delivery.

-An ATX supply has so many separate outputs one cannot even imagine what can be done with. I connected only three 12V and three 5V outputs and I fixed with screws the other ones.

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The great Nikola Tesla:

Ere many generations pass, our machinery will be driven by a power obtainable at any point of the universe. This idea is not novel. Men have been led to it long ago go by instinct or reason. It has been expressed in many ways, and in many places, in the history of old and new. We find it in the delightful myth of Antheus, who drives power from the earth; we find it among the subtle speculations of one of your splendid mathematicians, and in many hints and statements of thinkers of the present time. Throughout space there is energy. Is this energy static or kinetic? If static, our hopes are in vain; if kinetic - and this we know it is for certain - then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature.

Experiments With Alternate Currents Of High Potential And High Frequency (February 1892).