Author Topic: Induction cooker without electronics  (Read 1581 times)

Offline Solhi

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Induction cooker without electronics
« on: November 09, 2022, 12:11:04 PM »
Hi all,
What made me join this forum was a post* by Downunder35M I stumbled over in my search engine, when I was looking for confirmation that using caps to resonate a coil was unnecessary.
* https://highvoltageforum.net/index.php?topic=437.msg2709#msg2709
As you all know has any conductor a natural self-resonance.
According me, the only thing you have to do is to feed it a frequency preferably close to it's resonance or a part of it to avoid harmonics or opposing the natural frequency.
I have to disclose that I'm extremely poor in using all the available formulas (just seem not to be able to use them), and not having any equipment (living in the bush on a tropical island) So all my assumptions are pure theoretical and based on bits and pieces what  others have discovered and tested.
Meaning that I have have used a lifetime to read me up and try to understand giants like Tesla and the maybe as giant underwood of all the people using their time to experiment, explain and even improve these theories.

Now I wish to test my theory about an alternative induction cooker, and hope you guys can learn me a thing or two and correct me if I seem to be way off. In advance, excuse me for when it seems I'm abusing your time.

Now my induction cooker:
I came in to this HV, HF world through reading Patrick Kelly and from there Don Smith this of course after all Nikola Tesla left behind. So my theory is based on this.

An induction cooker needs a working coil that  has a strong enough alternating magnetic field at high enough frequency to induce powerful Eddy current in the ferromagnetic cookware.

Looking around I'm seeing they mainly use frequencies in the 20-80 KHz range.
My first question is now: does it need to? Would frequencies in the 100 MHz not be as good? This is of course the frequency of an working coil in self resonance with standing waves, giving maximum current and magnetic flux.

This cooker is ment to be used local here with a square 30*30 cm 20 liter stainless steel vessel to cook rice.
This requires an output of 6-8 Kw according my estimate.

My thought solution is a square pancake coil made of 2 mm copper wire. Since,  as far as I know, current at these high frequencies travel outside the wire, I do not need to worry about heat.
Such a coil would approximately need using Coil32 - Multilayer coil on a rectangular former

Input data:
Number of turns N = 54.0
Width of the former a = 100.0 mm
Height of the former b = 100.0 mm
Winding length l = 2.0 mm
Wire diameter d = 2.0 mm
Wire diameter with insulation k = 5.0 mm

Result:
Inductance L = 1381.958 µH
Winding thickness c = 270.0 mm
DC resistance of the coil Rdc = 0.282 Ohm
Wire length without leads lw = 51.3 m
Weight of wire m = 1444.027 g
Number of layers Nl = 54

So wire length 51.3 + leads = 51.5 m
Would give a self resonance of
1/4 wavelength / wirelength = Mhz
75,29/ 51.5 = 1.46 Mhz

Maybe the gap between the turns could be a bit bigger?

Next feeding this coil in the same freq. range
and enough current would suffice with 80V and 80 A

Which I think to get from an air coil transformer 24=>80V with a split secondary delivering the same amount of volts and amperes.

I hope my explanation was clear and not the least obtainable.

Offline klugesmith

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Re: Induction cooker without electronics
« Reply #1 on: November 09, 2022, 05:11:34 PM »
Welcome, Solhi.

Frequency must be chosen to avoid interfering with wireless communication.
So induction heaters/cookers (and microwave ovens and diathermy apparatus)
generally use ISM bands, which are scattered over many decades of the radio spectrum.

Your estimate of 6 to 8 kilowatts seems high for cooking rice.  Can you get away with 1 or 1.5 kW, available from ordinary household wall plugs, and wait a little longer to boil water in your 20 liter pot?

It's not clear how you will get power into a high frequency resonant circuit, without using electronics.
It was done for many decades without semiconductors, and I have tested a semiconductor-free microwave oven.

Offline Twospoons

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Re: Induction cooker without electronics
« Reply #2 on: November 09, 2022, 10:36:53 PM »

Looking around I'm seeing they mainly use frequencies in the 20-80 KHz range.
My first question is now: does it need to? Would frequencies in the 100 MHz not be as good? This is of course the frequency of an working coil in self resonance with standing waves, giving maximum current and magnetic flux.


You can answer this with a simple thought experiment:
If the frequency goes to zero, then no energy is transferred - so we can infer there is a minimum frequency which will effectively transfer energy.
If the frequency becomes extremely high, then the skin depth in the receiving metal becomes extremely small - as a consequence the resistance to the circulating current becomes very high and virtually no current flows. So very little energy gets transferred.  From this we can infer there is a maximum  frequency to effectively transfer energy.

Between these extremes there will be an optimum working frequency, one which matches the impedance of the source (the work coil) to the impedance of the load (the cook pot) in order to get the best power transfer.  Industry has clearly decided this is in the 20kHz to 80kHz range. 
There are other considerations, of course - kW level drivers in the sub 100kHz region are much simpler than kW level drivers in the 100MHz range.  The coils are simpler to build too.  Radio frequency compliance has already been mentioned.

Since,  as far as I know, current at these high frequencies travel outside the wire, I do not need to worry about heat.

This is fundamentally incorrect - the current still travels in the wire, but only in the surface at high frequencies ( look up 'skin depth'). This makes self heating of the wire worse at high frequencies, not better.

Offline Solhi

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Re: Induction cooker without electronics
« Reply #3 on: November 10, 2022, 09:01:31 AM »

Welcome, Solhi.

Frequency must be chosen to avoid interfering with wireless communication.
So induction heaters/cookers (and microwave ovens and diathermy apparatus)
generally use ISM bands, which are scattered over many decades of the radio spectrum.

Thanks klugesmith
I was aware of that problem with RF interference and therefore included a aluminum pan/case under and round the coil. The cookware shields the top

Quote
Your estimate of 6 to 8 kilowatts seems high for cooking rice.  Can you get away with 1 or 1.5 kW, available from ordinary household wall plugs, and wait a little longer to boil water in your 20 liter pot?

The locals boil on gas and for a similar size pan (10 Kg rice) they use 40-50 minutes.

My calculation of 6-8 KW is based on formulas from:

https://www.batteryequivalents.com/how-long-does-it-take-for-water-to-boil.html

Which indicates a need of 6 KW to boil 15 liters of water in the same time or preferrable shorter.
I'm still of the opinion that the K watts are easy to fetch following Tesla.

Quote
It's not clear how you will get power into a high frequency resonant circuit, without using electronics.
It was done for many decades without semiconductors, and I have tested a semiconductor-free microwave oven.

As you already write it is done before.
I did write:"Which I think to get from an air coil transformer 24 => 80V with a split secondary delivering the same amount of volts and amperes."
But maybe I need to elaborate that?



If the frequency becomes extremely high, then the skin depth in the receiving metal becomes extremely small - as a consequence the resistance to the circulating current becomes very high and virtually no current flows. So very little energy gets transferred.  From this we can infer there is a maximum  frequency to effectively transfer energy.

Hmm, this past my radar, need to dive into that.

Quote
There are other considerations, of course - kW level drivers in the sub 100kHz region are much simpler than kW level drivers in the 100MHz range.  The coils are simpler to build too.

I agree if you are talking about electronic drivers. But using air core transformers it is just a matter of adjusting conductor length to hit the right frequency.

Quote
"Since,  as far as I know, current at these high frequencies travel outside the wire, I do not need to worry about heat."

This is fundamentally incorrect - the current still travels in the wire, but only in the surface at high frequencies ( look up 'skin depth'). This makes self heating of the wire worse at high frequencies, not better.

I will check this up once more, but according to what I remember it would be just the opposite.
So called "cold electricity"

Thanks so far guys, you gave me some challenge, I take it :)
« Last Edit: November 10, 2022, 09:05:26 AM by Solhi »

Offline klugesmith

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Re: Induction cooker without electronics
« Reply #4 on: November 10, 2022, 05:49:36 PM »
>> I did write:"Which I think to get from an air coil transformer 24 => 80V with a split secondary delivering the same amount of volts and amperes."  But maybe I need to elaborate that?

Yes please.  How will the air core transformer do anything useful when fed by DC or mains frequency AC, without some switching?  There is a limit to energy transferred with each opening or closing of the switch. In SGTC the spark gap is the switch.

>> I was aware of that problem with RF interference and therefore included a aluminum pan/case under and round the coil.

How many dB of attenuation are necessary?   The shielding in a household MWO can be enough to meet safety limits, and still leak enough to jam nearby WiFi without violating any emissions regulation.
What fraction of your induction heating power will go into your aluminum pan/case instead of the cookware?   

>> My calculation of 6-8 KW is based on formulas from:
https://www.batteryequivalents.com/how-long-does-it-take-for-water-to-boil.html

I agree with your heating time and power predictions.  That's a nice site you pointed to, but it does include some mistakes.  For example, regarding electric kettles: "On average, in order to boil 1 liter of water, 1500W kettle requires ~4 min and 2500W kettle requires 2-3 min. An electric kettle is not as an efficient heater as a microwave oven, since there is a large "parasite" mass to be heated, but there is no danger of superheating the water."  The writer overlooks the elephant in room: power loss in conversion from mains frequency power to microwaves.  When MWO is running, the hot exhaust air is carrying waste heat from the magnetron.

Offline petespaco

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Re: Induction cooker without electronics
« Reply #5 on: November 10, 2022, 06:13:40 PM »
Quote
I will check this up once more, but according to what I remember it would be just the opposite.
So called "cold electricity"

My experience is limited to 1 to 2.5 KW ZVS induction heaters, but I can tell you from lengthy experience that the work coils DO heat up substantially,  These systems  (and the much larger ones) DO require that the work coils be made of copper tubing and that copper tubing must be water cooled.
I don't know why those HOBs (household induction cookers) manage to keep their work coils cool enough.

Offline Twospoons

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Re: Induction cooker without electronics
« Reply #6 on: November 10, 2022, 09:05:07 PM »
Induction hobs typically use Litz wire coils so the useable copper cross-section is much larger than with copper pipe, and hence the resistance, and self-heating, is much lower.

Offline Solhi

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Re: Induction cooker without electronics
« Reply #7 on: November 11, 2022, 05:26:32 AM »

Yes please.  How will the air core transformer do anything useful when fed by DC or mains frequency AC, without some switching?  There is a limit to energy transferred with each opening or closing of the switch. In SGTC the spark gap is the switch.

The "switching" is created by the 24V AC feed to the primary coil at any frequency. The length of the primary is tuned to the secondary at self resonance which will overrule any other frequency.

My "textbook" you can download here:
http://www.free-energy-info.tuks.nl/PJKBook.html

Quote
The shielding in a household MWO can be enough to meet safety limits, and still leak enough to jam nearby WiFi without violating any emissions regulation.

To jam a frequency you need to broadcast the same frequency with a stronger signal. WiFi is in the 1.6 - 5 GHz. What can be interfered is AM shortwave radio. But I doubt the signal will be strong enough.

Quote
What fraction of your induction heating power will go into your aluminum pan/case instead of the cookware?

The aluminum shielding interferes with the radiation downwards, which is lost anyhow.

Quote
That's a nice site you pointed to, but it does include some mistakes. 

I was only using the calculation how much K-joule => Kw I needed to heat the water itself.
The examples how much time an utensil uses is maybe only based on that not including possible losses and can therefore be invalid.

The other posts referring to how traditional induction heaters are build have no relevance, since this proposal is trying to eliminate this.
The post from Twospoons regarding skin effect is very useful, since it forces me to dive into the cold electricity again.

BTW, interestingly the skin depth at 60 KHz is close to that at 1 MHz for steel. As you can see ca. 1 KHz to 1 MHz is pretty flat, so I doubt that your claim that "Industry has clearly decided this is in the 20kHz to 80kHz range" has any value.

https://incompliancemag.com/article/skin-effect-and-surface-currents/
« Last Edit: November 11, 2022, 05:36:31 AM by Solhi »

Offline Twospoons

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Re: Induction cooker without electronics
« Reply #8 on: November 12, 2022, 12:42:54 AM »
What you are seeing with the steel is the effect of complex permeability.  Remember the induction hobs are probably also try to cope with copper, stainless steel and aluminium cookware as best they can.

I looked at your "textbook". It has a chapter on chemtrails  ::) . Massive red flag.  There maybe be other parts of this ebook which have correct information, but you really need to get some other books too, and not just from other  'free energy' sites of dubious provenance.

Quote
The "switching" is created by the 24V AC feed to the primary coil at any frequency. The length of the primary is tuned to the secondary at self resonance which will overrule any other frequency.

So you want to feed 24VAC 50Hz or 60Hz into a coil with a self-resonant frequency ~100MHz, and you expect the coil to just start oscillating at 100MHz?  Because thats not going to happen.  Because physics.

Quote
To jam a frequency you need to broadcast the same frequency with a stronger signal.
No, all you need to do is raise the in-band noise floor enough to disrupt the data flow.  Doesn't have to be a stronger signal.  (Further reading: look up Shannon's Law, which relates bandwidth and noise to theoretical maximum information throughput).  Also most receivers include some form of down-conversion to an intermediate frequency, and you can sometimes create a jamming signal at that frequency too (depending on how well constructed the receiver is).
« Last Edit: November 12, 2022, 12:45:24 AM by Twospoons »

Offline Solhi

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Re: Induction cooker without electronics
« Reply #9 on: November 16, 2022, 11:43:49 AM »

@Twospoons I might comment later.
In the meantime your previous comment made me dive into the alternative world. More precise the TBPC or Tesla Bifilar Pancacke Coil.
One of it's merits is that it according to many years testers it cancels out impedance so only the wire resistance is left.
Anyhow I did an attempt to visualize it in the simulator app on my phone, and yes the result is scary, anyhow for the capacitor.
Guess it will explode.
BTW the little cap should give 40 KHz
A Screen video you find here
https://filetransfer.io/data-package/WwnPHxnv#link

HMM, something went wrong. Can not repeat the results in the app. Not good, have to look in it.
« Last Edit: November 16, 2022, 02:13:29 PM by Solhi »

Offline Solhi

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Re: Induction cooker without electronics
« Reply #10 on: November 18, 2022, 05:21:52 AM »
I am playing around with a simulator but do not really understand the results I get. Maybe the more capable members can guide me.
The simulator depicts a TBPC in series feed with a DC source and a capacitor that should control the frequency to 40 kHz.
The attached screenshots show the results. Does this indicate very strong pulsing magnetic fields?

Offline Twospoons

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Re: Induction cooker without electronics
« Reply #11 on: November 18, 2022, 06:29:23 AM »
No, it indicates you need to learn about SPICE simulators.  You've drawn a circuit with 'perfect' components - your L and C have no resistance, and there's no resistance anywhere else either. Its also supplied with a  voltage source, which in simulator world can supply infinite current.   So you have a circuit with infinite Q, which will happily ring forever.  The result you are seeing is nonsense, and bears no resemblance to the real world.
The simulator doesn't care though, its just doing what you asked it to.

Offline klugesmith

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Re: Induction cooker without electronics
« Reply #12 on: November 18, 2022, 06:54:55 AM »
How did you model the bifilar pancake coil?
Suppose we think of it as two windings occupying nearly the same space, so tightly coupled, each with inductance L.
A model with two identical L's in series, for total of 2L, is wrong.
If the inside of one coil connects to outside of the other coil, the combination gives you 4L. (Realizable in simulation by drawing two identical L's and setting a coupling factor of 1 or 0.999.)

In previous post you talked about canceling inductance. That would happen if inside of one winding connected to inside of other winding, so current in adjacent turns flows in opposite directions.  Net inductance is zero.   Realizable in simulation by keeping the coupling factor of 1 or 0.999 but reversing connections to one winding.  Or erase both L's and just place a single R to represent wire resistance, as you said in previous post.  Of course it won't resonate with any capacitor !

What online (?) simulator are you using?  Looks like current is shown by animated moving dots.   I want to see if they represent electron drift direction (bad) or direction of charge transport (good) or user gets to choose (even better).
« Last Edit: November 18, 2022, 06:57:24 AM by klugesmith »

Offline Solhi

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Re: Induction cooker without electronics
« Reply #13 on: November 18, 2022, 11:38:44 AM »
How did you model the bifilar pancake coil?
Suppose we think of it as two windings occupying nearly the same space, so tightly coupled, each with inductance L.
A model with two identical L's in series, for total of 2L, is wrong.
If the inside of one coil connects to outside of the other coil, the combination gives you 4L. (Realizable in simulation by drawing two identical L's and setting a coupling factor of 1 or 0.999.)

Ås there is nowhere a TBPC included in any of these Apps. I just thought wrong and inserter 2 L with the same inductance. Indeed you are right it should be 4 L. So I adjust the model by choosing a transformer model with the coupling factor just given by you and connect the coils in series?

@Twospoons thanks for your info, learns me not to be so gullible :/
Edit: Found hidden in the app a wire resistance switch which was off. Diametral different result.

Quote
In previous post you talked about canceling inductance. That would happen if inside of one winding connected to inside of other winding, so current in adjacent turns flows in opposite directions.  Net inductance is zero.   Realizable in simulation by keeping the coupling factor of 1 or 0.999 but reversing connections to one winding.  Or erase both L's and just place a single R to represent wire resistance, as you said in previous post.  Of course it won't resonate with any capacitor !

I did write it canceles impendance not inductance. This should be according Tesla himself. Aka resistance will never be more than the wire resistance.

Quote
What online (?) simulator are you using?  Looks like current is shown by animated moving dots.   I want to see if they represent electron drift direction (bad) or direction of charge transport (good) or user gets to choose (even better).

I used the android app "PROTO" I will check what the animation represents.
« Last Edit: November 18, 2022, 12:28:06 PM by Solhi »

Offline klugesmith

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Re: Induction cooker without electronics
« Reply #14 on: November 18, 2022, 05:48:00 PM »
>> I did write it cancels impedance not inductance. This should be according Tesla himself. Aka resistance will never be more than the wire resistance.

You're making progress, Solhi.   Your transformer model will work, with the well-coupled inductors in series.  You can get 4L with no canceling of impedance.  Or you can get 0L by reversing the series connection to cancel impedance.  Please try it both ways & report result.

Do you want TBPC to behave as an inductor in resonant circuit, or as a noninductive wire resistor?   Tesla (pbuh) never expected both in the same coil at same time.

Offline Solhi

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Re: Induction cooker without electronics
« Reply #15 on: November 19, 2022, 06:38:00 AM »
>> I did write it cancels impedance not inductance. This should be according Tesla himself. Aka resistance will never be more than the wire resistance

Do you want TBPC to behave as an inductor in resonant circuit, or as a noninductive wire resistor?   Tesla (pbuh) never expected both in the same coil at same time.

My idea was generating very strong magnetic pulses without generating the heath. I still think I need to generate 6 KW in the cookware

Offline Solhi

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Re: Induction cooker without electronics
« Reply #16 on: November 19, 2022, 02:30:04 PM »
My results for the moment are not loyal to the title of the thread :-[
But to get some result I borrow some electronics which I later must try to substitute with a sparkgap of some sort.
Maybe a gas discharger.
Anyhow my question now is: do the spikes as a result of back EMF shown in the sim. create enough EM pulses to create useful induction and how would one convert that to power?
I have heard that electric waves that go in the negative phase converts to magnetic energy.

Offline Solhi

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Re: Induction cooker without electronics
« Reply #17 on: November 20, 2022, 10:00:13 AM »
Found out that I need close to the Max allowed magnetic flux of 26 uT. Have not been able to find any example of how much aTBPC can generate. For sim users I found a post describing how to model a Tesla coil in Sim. I need a desktop computer to do that.
https://overunity.com/17186/the-bifilar-pancake-coil-at-its-resonant-frequency/msg505402/topicseen/#msg505402

Offline klugesmith

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Re: Induction cooker without electronics
« Reply #18 on: November 20, 2022, 07:17:36 PM »
Please explain where you got 26 microtesla limit.   Do you have very sensitive instruments, to detect any heating from induced currents in 26 uT field at any frequency?

[edit] My previous comments about bifilar pancake coils, and coupled inductor/transformer model, neglected the capacitance between turns.  That does contribute to energy storage, and behavior associated with transmission-line wave propagation in spiral paths.

But the circuit model shown in that overunity post represents a single ordinary symmetric transmission line, appropriately modeled as a ladder of discrete L's and C's. I see no "cross coupling", that is to say any magnetic or capacitive coupling between turns of the bifilar wire pair.   In the course of a century, there must have been serious attention to theory and practice of TBPC behavior, but none appears in that post. Don't rush to get a desktop computer just to repeat that lame exercise.
« Last Edit: November 20, 2022, 09:55:27 PM by klugesmith »

Offline Solhi

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Re: Induction cooker without electronics
« Reply #19 on: November 21, 2022, 03:09:26 PM »
Please explain where you got 26 microtesla limit.   Do you have very sensitive instruments, to detect any heating from induced currents in 26 uT field at any frequency?

From bfs.de
"At common distances to the hobs the appliances usually comply with the reference value of 27 µT for the magnetic flux density developed for the relevant frequency range by the International Commission on Non-Ionizing Radiation Protection (ICNIRP Guidelines 1 Hz – 100 kHz, 2010)"

https://www.bag.admin.ch/dam/bag/de/dokumente/str/nis/faktenblaetter-emf/b-field-exposure.pdf

Quote
[edit] My previous comments about bifilar pancake coils, and coupled inductor/transformer model, neglected the capacitance between turns.  That does contribute to energy storage, and behavior associated with transmission-line wave propagation in spiral paths.

There I am completely blank (empty gaze)


Quote
In the course of a century, there must have been serious attention to theory and practice of TBPC behavior, but none appears in that post. Don't rush to get a desktop computer just to repeat that lame exercise.

Well, the strange thing is, if it was, it is damned good hidden. I can't find anything. The best source is the ppl. in these forums and they do a serious amount of work without me being able to find anything that definitive closes the case.

I should have disclosed that I'm situated on a topic island without easy access to anything and in addition minimal funds to use. Further do I not have any useful place to work and even less the instruments. The most advanced is the sim on my phone and a old Fluke multimeter.
I admit, it can, until I have found out the what and how, only be a theoretical exercise.
« Last Edit: November 21, 2022, 03:24:25 PM by Solhi »

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Re: Induction cooker without electronics
« Reply #19 on: November 21, 2022, 03:09:26 PM »

 


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November 28, 2022, 03:26:55 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
klugesmith
November 28, 2022, 02:09:06 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
alan sailer
November 28, 2022, 12:06:02 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 27, 2022, 06:05:52 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 27, 2022, 01:24:05 PM
post Re: ZVS driver won't oscillate
[Electronic Circuits]
davekni
November 27, 2022, 06:21:04 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 27, 2022, 01:13:28 AM
post Re: Oh Lawd, I got dem Op-Amp blues!
[General Chat]
AkashaStar
November 26, 2022, 06:49:16 PM
post Re: ZVS driver won't oscillate
[Electronic Circuits]
AstRii
November 26, 2022, 04:48:39 PM
post Re: IF D95T vs IF D95OC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
RoamingD
November 26, 2022, 06:56:51 AM
post Re: IF D95T vs IF D95OC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alexhanyuan
November 25, 2022, 11:28:15 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 25, 2022, 12:05:50 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 25, 2022, 07:53:52 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 24, 2022, 08:08:48 AM
post Re: EEFL backlight circuits
[Light, Lasers and Optics]
klugesmith
November 24, 2022, 07:26:49 AM
post Re: Air cored inductors proximity to conductive objects
[General Chat]
davekni
November 24, 2022, 03:02:11 AM
post Re: Solid State “rheostat” that will withstand high electrostatic fields
[General Chat]
AkashaStar
November 24, 2022, 02:25:42 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 24, 2022, 01:45:33 AM
post Re: Air cored inductors proximity to conductive objects
[General Chat]
John123
November 23, 2022, 11:27:18 PM
post Stepper motor drive without switching
[Electronic Circuits]
klugesmith
November 23, 2022, 10:23:07 PM
post Re: Air cored inductors proximity to conductive objects
[General Chat]
Twospoons
November 23, 2022, 09:29:01 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Alberto
November 23, 2022, 08:45:37 AM
post Re: Air cored inductors proximity to conductive objects
[General Chat]
davekni
November 23, 2022, 04:44:20 AM
post Air cored inductors proximity to conductive objects
[General Chat]
John123
November 23, 2022, 01:10:17 AM
post Re: Post-Soviet Tesla Coil Teardown and Test
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
November 22, 2022, 08:40:19 PM
post Re: Ericsson RBS 6601 RRUS 12 analysis(kind of)
[Electronic Circuits]
Da_Stier
November 22, 2022, 08:22:09 PM
post Re: Ericsson RBS 6601 RRUS 12 analysis(kind of)
[Electronic Circuits]
Kirby4life
November 22, 2022, 08:45:06 AM
post Ericsson RBS 6601 RRUS 12 analysis(kind of)
[Electronic Circuits]
RickNitro
November 22, 2022, 08:36:11 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
davekni
November 22, 2022, 06:42:31 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Twospoons
November 22, 2022, 06:40:32 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
klugesmith
November 22, 2022, 04:53:40 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Twospoons
November 22, 2022, 02:17:08 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
klugesmith
November 21, 2022, 11:03:04 PM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Alberto
November 21, 2022, 09:55:02 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 21, 2022, 03:09:26 PM
post Re: Post-Soviet Tesla Coil Teardown and Test
[Solid State Tesla Coils (SSTC)]
LoOdaK
November 21, 2022, 09:38:22 AM
post Re: Trichel pulses
[Electronic Circuits]
klugesmith
November 20, 2022, 10:05:15 PM
post Trichel pulses
[Electronic Circuits]
haversin
November 20, 2022, 09:48:37 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 20, 2022, 07:17:36 PM
post Re: Some questions about my first drsstc.
[Dual Resonant Solid State Tesla coils (DRSSTC)]
mthome4
November 20, 2022, 02:28:22 PM
post Post-Soviet Tesla Coil Teardown and Test
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
November 20, 2022, 02:03:49 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 20, 2022, 10:00:13 AM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
davekni
November 20, 2022, 05:13:12 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
davekni
November 20, 2022, 05:08:31 AM
post Re: Plasma Toroid
[Solid State Tesla Coils (SSTC)]
alan sailer
November 20, 2022, 01:27:00 AM
post Re: Basic Gate driving doubts
[Solid State Tesla Coils (SSTC)]
davekni
November 19, 2022, 10:12:14 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
John123
November 19, 2022, 09:57:35 PM
post Re: Basic Gate driving doubts
[Solid State Tesla Coils (SSTC)]
prabhatkumar
November 19, 2022, 09:50:23 PM
post Re: Basic Gate driving doubts
[Solid State Tesla Coils (SSTC)]
davekni
November 19, 2022, 08:26:45 PM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
davekni
November 19, 2022, 06:53:17 PM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
klugesmith
November 19, 2022, 06:05:47 PM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Alberto
November 19, 2022, 05:34:46 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 19, 2022, 02:30:04 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
AkashaStar
November 19, 2022, 01:56:10 PM
post Re: Buck converter question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
dru
November 19, 2022, 08:03:56 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 19, 2022, 06:38:00 AM
post Basic Gate driving doubts
[Solid State Tesla Coils (SSTC)]
prabhatkumar
November 19, 2022, 05:37:09 AM
post Re: ZVS driver won't oscillate
[Electronic Circuits]
davekni
November 19, 2022, 03:59:56 AM
post Re: Non-laser pointer
[Light, Lasers and Optics]
klugesmith
November 19, 2022, 03:56:32 AM
post Re: Buck converter question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
November 19, 2022, 03:36:20 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
davekni
November 19, 2022, 03:26:48 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
Alberto
November 19, 2022, 12:40:33 AM
post Re: ZVS driver won't oscillate
[Electronic Circuits]
AstRii
November 18, 2022, 09:32:33 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 18, 2022, 05:48:00 PM
post Re: Audio Modulated CRT Flyback Transformer Loud Sparks
[Transformer (Ferrite Core)]
John123
November 18, 2022, 03:49:12 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
John123
November 18, 2022, 02:56:49 PM
post IF D95T vs IF D95OC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
RoamingD
November 18, 2022, 01:44:38 PM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 18, 2022, 11:38:44 AM
post Non-laser pointer
[Light, Lasers and Optics]
klugesmith
November 18, 2022, 10:05:29 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
klugesmith
November 18, 2022, 06:54:55 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Twospoons
November 18, 2022, 06:29:23 AM
post Buck converter question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
dru
November 18, 2022, 06:10:52 AM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
davekni
November 18, 2022, 05:53:15 AM
post Re: Induction cooker without electronics
[Electronic Circuits]
Solhi
November 18, 2022, 05:21:52 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
davekni
November 18, 2022, 04:00:04 AM
post Re: Vacuum pump
[Laboratories, Equipment and Tools]
alan sailer
November 17, 2022, 10:24:35 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
John123
November 17, 2022, 08:30:00 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
klugesmith
November 17, 2022, 07:28:16 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
John123
November 17, 2022, 03:38:00 PM
post Re: TV flyback number of primary turns rule of thumb
[Transformer (Ferrite Core)]
davekni
November 17, 2022, 04:03:51 AM
post Re: what type of diode is better for make high voltage diode?
[Voltage Multipliers]
davekni
November 17, 2022, 03:57:40 AM

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