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Author Topic: Joule Thief 101  (Read 926728 times)

sm0ky2

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Re: Joule Thief 101
« Reply #150 on: February 10, 2016, 05:08:37 PM »
Smoky2:

A coil at it's SRF is either dead and blocks AC if you model it as a parallel resonant tank or it's dead and offers no resistance to AC if you model it as a series LC tank.  In either case the inductance is nowhere to be found.  Above the SRF it just looks like a capacitor.

Why should a coil at its SRF enhance the performance of a Joule Thief when it is effectively dead and not functioning properly? 


If you really wanted to be sure you could inject a signal into the coil and look for the SRF.

In broad general terms, the "buzz" about a coil operating at its SRF on the free energy forums is a bunch of BS.  You are effectively turning the coil into a piece of wire or an open circuit.  There is nothing exciting about that.  There is no "secret sauce" related to hacking a JT and turning it into an oscillator and running it at the SRF of the main coil.  There is a very decent chance that the oscillation would in fact die at the SRF because the main coil of the JT becomes inert at the SRF frequency.

MileHigh

The first two points go hand in hand. We have had scopes all over this thing, across the transistor, across the diode, across the coil, across the base resistor, even observed the ends of the battery at times.
When all other factors of the system remain the same, coil, core, voltage, transistor, led.
and all you adjust is the resistance across the base - you are changing the injected feedback signal, and how it applies to the next iteration of the cycle. This signal is not present at points other than a resonant node. It is inversely canceled out by its counterpart in the circuit. no reflection, no collapse of the parasitic capacitance at the peak.

To the latter issue, I agree, most of what people talk about in these regards is total b.s.
what I am doing here is presenting the facts along with the electrical theory, and experiments to get rid of all the mysticism and "magic" ideas floating around.
When this is all out in the open, where people can understand and experiment with this, then concepts like "secret sauce" need no longer apply.
You can't look at a Resonant circuit, in terms of how a component at SRF would perform in a non-resonant circuit.
You have to look at the whole picture.

The coil will always retain a positive value for inductance, because of the 3rd parasitic relationship of the circuit at SRF.
The resistance of the circuit has a parasitic inductance, and the ferrite will still magnetically charge.
That is the whole point of this exercise

- the "indoctrination" is that instinctive feeling you get when you head down this road, and makes you want to stay away from the SRF. It is perfectly normal after years of accredited education. We all go through it......



Magluvin

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Re: Joule Thief 101
« Reply #151 on: February 10, 2016, 06:52:23 PM »
Smoky2:

The information in Magluvin's book is pertinent and says it all.  You stay away from the SRF of the coils in a switching power supply because at the SRF the coils crap out and don't function as coils anymore.  You even stay away from having a harmonic of your excitation frequency line up with the SRF of the coils.  The excitation is a pulse train with sharp edges so naturally the signal is very high in harmonics.

A coil at it's SRF is either dead and blocks AC if you model it as a parallel resonant tank or it's dead and offers no resistance to AC if you model it as a series LC tank.  In either case the inductance is nowhere to be found.  Above the SRF it just looks like a capacitor.



MileHigh

I posted that as an example of it is said that we shouldnt partake in srf functions when designing a power supply. I dont believe it is saying that the inductor is dead.

What Im seeing it says is that the rise in current if the inductor when the transistor turns on(in a typical regulator design) is too quick for the driver design. What  that tells me is that the on time is too long in this case.  So what Im looking at is how to design the circuit to accommodate that higher freq of operation.

As with the cores SRF, what Im thinking is that if we design the coils SRF to match a lower multiple of the cores SRF, there may be some advantages as Smoky says. Will have to be tested.

Havnt built a JT yet. But from what Smoky says about the variable resistor on the base, it must be adjusting the on time and getting the SRF mode to ring.

I find it to be interesting stuff. ;D


Back when the Russian guys were playing with tv flyback transformers, I believe they were talking about the cores SRF function in what they were doing. What did they call it, NMR? But, there were claims of dangerous radiations from the cores running at core SRF freq.  I would like to avoid that if possible.

Mags

MileHigh

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Re: Joule Thief 101
« Reply #152 on: February 11, 2016, 03:18:10 AM »
Well at least differing opinions were aired and that's always a good thing.  Perhaps there are some people building Joule Thieves that will do their own investigations and also get inspiration from the comments in this thread.

Let's assume that your design goal is a fairly bright LED with no flickering (to the human eye) with minimum power draw from the battery.  There can be other design goals, the one I am suggesting would seem to be the most logical one for me.

It brings up the issue of apparent brightness.  I was told once that it is a zero sum game.  A very bright flashing LED with a short duty cycle will have the same apparent brightness as a medium bright LED with a longer duty cycle such that the power draw from the battery is approximately the same in both cases.  Is that really true?  I don't know.

Nonetheless, it suggests there is a "Goldilox" core size and an associated Goldilox Joule Thief transformer configuration to give you a "sweet train of pulses" to keep the LED lit with minimum battery draw.

I doubt anybody would go that far but if we end up fighting WW IV with rocks then who knows?

MileHigh

Magluvin

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Re: Joule Thief 101
« Reply #153 on: February 11, 2016, 05:09:44 AM »
So. Since this is a JT thread, might as well start there and test these things. A JT is the simplest circuit to play with.

Any suggestions as to what works best making one of these? Has anyone wound their transformers bifi? I figure more capacitance, lower freq SRF.

I have lots and lots of parts.  100mhz scope(200 if I do the hack for the hantek 5000 series.)   Near dead batteries of all sorts.

Mags

Magluvin

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Re: Joule Thief 101
« Reply #154 on: February 11, 2016, 07:06:51 AM »
Went to beginning of the thread and getting stuff together.

Mags

allcanadian

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Re: Joule Thief 101
« Reply #155 on: February 11, 2016, 07:15:02 AM »
It's nice to see the JT threads are still active and I remember the good old days when it was first introduced here. Not long after a man named Dr.Stiffler appeared for a while with a variant and I found one of his oscillators I bought under my bench collecting dust only a few weeks ago. It was basically a glorified low power high frequency JT in my estimation from the testing I did. The work I posted closely related to Stifflers designs was then borrowed and morphed into the infamous Slayer circuit. Strange how I had numerous slayer circuits built and tested at least a year before he supposedly "invented" them, lol, such is life. Even more curious is that the odd article still pops up by some EE or electronics expert claiming they don't really understand it and that it is a marvel of engineering.


A few tips, early on I found the base or gate resistance dissipates as much energy as the load in some cases. LED's on the base lit almost as bright as the supposed load so a series cap should be used. I transitioned to open gate mosfet switching with a bare wire on the gate not attached to anything or the gate wire wrapped around the insulation of a HV secondary. This design morphed into self-oscillating(self-switching) SS HV induction coils not unlike a Rhumkorff or Tesla coil. It's odd that so many consider parasitic capacitance, a ridiculous term, as a problem when in many cases it is the best solution if not the only one.


How do you switch an external electronic circuit when the primary circuit your trying to synchronize to is blowing off 12" arcs in every direction, inducing ridiculous voltages in all nearby open conductors?... the answer is you can't to my knowledge. I had random nuts and bolts and wires scattered on the bench arcing over up to 1" apart like a christmas tree three feet away from my quite unique oscillator. I wouldn't put any oscilloscope within 20 feet of that infernal machine and it made my Tesla coil look like a fart in a windstorm. Good times back then, exciting times and there was a lot of crazy shit going on, a lot of creativity and as always a lot of wild ass speculation.


In any case...play safe.


AC






ramset

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Re: Joule Thief 101
« Reply #156 on: February 11, 2016, 08:46:10 AM »
Mags
we know things come apart at resonance ,we know plain heat will do like wise ,as well as the hammer shown here

https://www.youtube.com/watch?v=XC6I8iPiHT8

and we know energy is released...

The Bug above hunts with Photons which he Knocks out of orbit ,he messes with the wheel work of nature so he can get a meal.

as Smoky has said, it would seem the education process has purposely kept different fields of science separated
by "specialty" or Box.

when it would seem that there is much to be learned By mixing it up ,and getting into a bit of Chaos outside the Box.

NMR,NAR ,LENR or something else ??

Rossi ,Alexander Parkhomov ,Constantine Balakirian, Steven Marks...Stanley Meyer  ...

its all the rage these days !

and it is our destiny.



« Last Edit: February 11, 2016, 02:38:47 PM by ramset »

tinman

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Re: Joule Thief 101
« Reply #157 on: February 11, 2016, 12:48:05 PM »
Went to beginning of the thread and getting stuff together.

Mags

Set up a bifilar coil with a steel laminated core,where the core is two separate halves -1 half will see the flow of charge into the magnetic center,and the other half will see the flow of charge out from the magnetic center. Set up a simple self oscillating circuit,and run the LED off the two core halves,where you two core halves act like capacitor plates,and are charged every pulse. this way you can bring your frequency up to a resonant state,where the amplitude is at maximum,and power draw at a minimum.

Brad

sm0ky2

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Re: Joule Thief 101
« Reply #158 on: February 11, 2016, 07:32:42 PM »
Theres a concept called negative capacitance. this is where the negative portion of the magnetic waveform is considered in the impedance equation. Basically considered as Reactance, in the electronics portion of the circuit.
Impedance = resistance + reactance(sqrt[-1])

Now,. we can't actually built a negative capacitor, (or can we?)
but mathematically, we can just throw the (-) out since we square it later in subsequent equations.
and replace the whole resonant mess with a capacitor of positive value.

This is the standard electronics model. Text books do not generally take this any further.
When we examine Inductance as being a proportional factor of Impedance and angular frequency
we essentially look at only the positive value of reactance.

we literally take the absolute value of this number, and apply it to already known electronics equations.

But negative capacitance can be calculated AND measured!!!  We know it exists,. but we assume it does not matter.
Or are (told) it does not matter....   Then we are shown other examples of when it actually matters.

Pay no attention to the man behind the curtain

L = X / w ; where L is inductance, X is reactance, and w is 2(pi)f

or we can take the "effective Q" = |X|/R ; <<<---- see, we can use this instead. and we don't have any pesky 0's in the division......

 We are trained this way from day 1.
This is what is, this is what is not, this is how we use it.
these are the things that are not what we told you at first,
and this is how to get rid of these "problems".


MileHigh

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Re: Joule Thief 101
« Reply #159 on: February 11, 2016, 09:46:01 PM »
Here is a clip that shows the Joule Thief schematic and gives a very good verbal description of how a Joule Thief works from start to finish.  It describes the Joule Thief as a switching device with positive feedback, which is exactly what I have been saying.  The word "resonance" is never stated.  The description is not too technical but it is verbose and complete and anyone that has a basic knowledge of electronics should be able to follow it and understand it.

https://www.youtube.com/watch?v=0GVLnyTdqkg

Now, that's in contrast to the previous two postings in this thread.  Sorry, but they are a bunch of mumbo-jumbo talk and both don't make any sense.  I know that it's not politically correct abound here to say this but it is what it is.

If you want to try to convince myself and others that you are making a valid case and supposedly making sense, then use the clip above as a standard that you can try to meet.  Fake pseudo electronics talk with nonsensical terms and the old "they don't want you to know" boogeyman talk just won't cut it.

sm0ky2

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Re: Joule Thief 101
« Reply #160 on: February 11, 2016, 10:56:40 PM »
Here is a clip that shows the Joule Thief schematic and gives a very good verbal description of how a Joule Thief works from start to finish.  It describes the Joule Thief as a switching device with positive feedback, which is exactly what I have been saying.  The word "resonance" is never stated.  The description is not too technical but it is verbose and complete and anyone that has a basic knowledge of electronics should be able to follow it and understand it.

https://www.youtube.com/watch?v=0GVLnyTdqkg

Now, that's in contrast to the previous two postings in this thread.  Sorry, but they are a bunch of mumbo-jumbo talk and both don't make any sense.  I know that it's not politically correct abound here to say this but it is what it is.

If you want to try to convince myself and others that you are making a valid case and supposedly making sense, then use the clip above as a standard that you can try to meet.  Fake pseudo electronics talk with nonsensical terms and the old "they don't want you to know" boogeyman talk just won't cut it.

This is the minimalist version of the circuit, that uses no consideration to system losses.
Yes it works, so does the filament lightbulb.

stating that it works and that we don't need to know any more than that to turn the lights on, is all fine in dandy.

But compare an old style filament bulb to a newer LED bulb of the same luminescence.
and compare their energy consumption

Now, do the same with the Joule thief.

Magluvin

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Re: Joule Thief 101
« Reply #161 on: February 11, 2016, 11:16:03 PM »
Set up a bifilar coil with a steel laminated core,where the core is two separate halves -1 half will see the flow of charge into the magnetic center,and the other half will see the flow of charge out from the magnetic center. Set up a simple self oscillating circuit,and run the LED off the two core halves,where you two core halves act like capacitor plates,and are charged every pulse. this way you can bring your frequency up to a resonant state,where the amplitude is at maximum,and power draw at a minimum.

Brad

Can you make a diagram of the cores and where the windings are on the cores. Sort of a magnetically induced capacitor?

Mags

Thanks

tinman

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Re: Joule Thief 101
« Reply #162 on: February 12, 2016, 12:27:16 AM »
Can you make a diagram of the cores and where the windings are on the cores. Sort of a magnetically induced capacitor?

Mags

Thanks

Exactly

tinman

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Re: Joule Thief 101
« Reply #163 on: February 12, 2016, 12:50:17 AM »
Can you make a diagram of the cores and where the windings are on the cores. Sort of a magnetically induced capacitor?

Mags

Thanks

Here is an earlier video showing the charge build up on the laminated core. This clearly shows the capacitor effect between the winding's,and the core it self. It also show's that some of the consumed current is due to this core charge being forcefully discharged during each pulse. By allowing this charge to be reduced by way of driving the LED,we can see less current is drawn by the circuit.

https://www.youtube.com/watch?v=cJB_cnx9Rx8


Brad

Magluvin

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Re: Joule Thief 101
« Reply #164 on: February 12, 2016, 02:51:36 AM »
Thanks Brad. Thats pretty cool. So if it was a long core without the separation there isnt any current through the core? Seems odd.  But Ill take your word for it. ;)

I wonder if you interleaved the laminations(insulated) some near the center to increase surface area if there might be helpful to generate more charge.

In this circuit below from a pdf on this thread, to me there seems to be a problem. Not that the circuit doesnt work. But the led is across the transistor in the same direction.  I understand that the batt doesnt have enough voltage to conduct the led. But when the transistor turns off, the inductors collapse current flows through the led AND the battery, thus further discharging the battery more besides the transisitor switching. So wouldnt it be better to put the led across the transformer winding where the batt isnt being drained during the led discharge also?

Mags