Self running coil?

[skywatcher]

This is correct; about @49ua  - 100uW is coming out from the caps.
I estimate about 200mW about 1/5W could be made available from
the pickup coil. - Because he hasn't done the max(P)=E^2/R. Which
would match the output impedance of the coil to the (1K) load resistor.
So this is *way* overunity.... If he would build the HF AC transformer/
voltage multiplier he could run the cap by charging it, running the current
backwards. Then solving that problem, we could prove OU on you-tube. 

I think it's time for a new circuit diagram... it's difficult to see it from the video.   

One problem for replication is that we don't know the exact properties of the ferrite core. There are many types of ferrite, and in most cases you don't know them. Additionally there are tape-cores like Nanoperm etc...

I never got any clear resonance with any of my cores.   

[gravityblock]

He didn't state what the pictured circuit was, I see something resonating
nicely along at eight volts to the gate and and something else not resonating
very well as the load. The load Q~=1.0 and the phase shift is nearly 180
degrees out-of-phase with the input - that's hard to do. It reminds me of
that air core coil.

:S:Mark

I think you're referring to a different experiment than I am.  I was referring to the toroid/air coil experiment and you're referring to his latest experiment.


GB

[gotoluc]

Hi everyone,

I made a new video to try to explain to the best of my understanding what makes this circuit work.

You can watch the video if you want but it's kind of boring as I'm not doing all that much.

Link to Video: http://www.youtube.com/watch?v=N8BehANEVUo

Here is how I understand it at this time.

A magnet is needed, a ferrite core seems to be important also but what I think is very  important is INDUCTANCE. This is what I mostly say in the above video, so you can watch it if you want or just read this.

Lets say we have a toroid or an open end FERRITE core coil an its inductance is 1 Henry. We know by adding a permanent magnet to the core the coils inductance will drop depending on the strength of the magnet or the saturation point of the core.

I'm quite sure the effect of returned energy works best with the strongest magnet! BUT as I stated above if the magnet is strong you may be left with next to no inductance. The 1 Henry coil you start with can easily go down to 10mH (Milli Henry)

What maybe happening when a permanent magnet (PM) is added to a coils core is when the coil is energized its electromagnetic field  pushes against the permanent magnet field and once the coil is switched off the PM flux bounces back. This is where the return energy is coming from.

Now if we think about it, then we want the most powerful bounce back. So we want a strong magnet!... BUT a strong magnet will reduce your inductance next to nothing as stated above!... who cares, just build it right!... Wrong!... Inductance is what your coil needs to be able to create a strong Electromagnetic field to push against those strong magnets. So if you're left with only 10mH your coil will need a high voltage with much current to be able to create a strong enough push against the PM.

Now for the other problem. If you wind a Mega Inductance coil that reaches the 10 Henry mark it will need much wire length... who cares, just build it right!... Wrong!...wire length give resistance and resistance gives energy losses and not to mention coil reaction time (electromagnetic field building time).

So all these things need to be considered to get the right balance. So what do we do?

I have found and been trying to demonstrate and share since my ORBO replication that if you wind 2 coils in perfect half moons on a ferrite core the Inductance is close to double then the standard single coil toroid. Would this not be a coil design to consider for the above project?... hum... let's see, twice the inductance and no extra resistance then the standard coil. Sounds good to me!  but you decide.

I built mine with 30 AWG which has much resistance and ended with only 6.9 Ohms and over 1 Henry inductance. I would recommend using 20 AWG or a thicker wire if your cores are large enough and wind it to 2 Henry or more if you can. But like I said many things need to be considered, like the total coil resistance, coil reactance time, PM strength to core saturation limit, the right inductance to push the pm field and also the right inductance to bring the coil to resonance. Yes! Resonance, another area to consider and important if you want the coil to be efficient.

Resonance is what's going on when I've been demonstrating the energy going back to the source. This is why I started this topic to bring this possibility to light.  JLN has not found this effect yet, as I think his residual inductance is very small with the magnets used. He would need a much high frequency then he's been using to see it. However I do agree with him that the energy comes from magnets push back when coil is switched off. The other thing  that is needed is a MOSFET as switch to see the resonance effect unless you add capacitance. It appears that the built in capacitance of a mosfet is what is most likely bringing the coil to resonance. I tried it with a regular transistor and nothing happens.

The other interesting finding I have is, the mosfet can self oscillate (switch) itself IF the right combination of inductance between the main coil and pulse coil (added between gate & source) as long as the circuit is tuned to the resonance range. By using a 3vdc feed, my dual coil toroid, IRF640 and tuning coil have achieved resonance to any frequency I want between 5KHz to 50KHz WITHOUT the use of capacitors. Many of the frequency Inductance values have been documented and someone from here is working out a formula that will be shared with all.

The above is the description to the best of my ability at this time of what is going on in the circuit at this time.

Hope this helps some to better understanding what I've been trying to share.

Luc

[gotoluc]

I can't speak for Luc, but I don't think his intent is to use the air coil.  What he was trying to demonstrate, is why does the circuit with an air coil and a lower resistance, perform worst than the same circuit with a toroid with a higher resistance, and they both are resonating at the same frequency and have the same inductance.  According to the text books, a circuit with a lower resistance should be more efficient than a circuit with a higher resistance when at resonance.....but it's not in Luc's experiment.

GB

GB, you're right on the money

Glad someone understands me and can explain it better than me

To all, I don't use the Brooks air core. It was just used for that video. My tuning coil is a ferrite core.

Luc

[gyulasun]

Hi Luc,

I wanted to answer for your Reply #377 above when I have just seen your latest mail with the new video.  Just finished reading and watching it and for a moment I wondered whether I include my reply written earlier or not because it would sound I am against any overunity... or that I explain away your findings with conventional text book talk.
Well, I can assure you I am very open to overunity, have been trying to think outside the box for a long time BUT still first I try to watch things first whether with conventional knowledge and experience I can or cannot understand a 'strange' circuit, a setup etc.  I am all for scientific reality, try to remain scientific and if I cannot undertand something then first I admit I do not know it and second I seek for help and dig into it if I can.

So here is my reply to your last but one mail #377, I did not change anything in it now that I have read your latest reply.

--------
Hi Luc,

Thanks for the answers, please when you have time measure the toroidal coil's inductance you have had in the oscillator with the scope shots. Is it still 113.5mH? Also, would be good to know the pulse coil's inductance and DC resistance, when separated from the gate-source pins, ok?

I do not agree that the IRF640 does not use external energy for its operation, sorry. The 3.8 mW or so power must be the reactive power inside the pulse coil which must be parallel resonant with the gate-source and gate-drain capacitors. This resonant circuit receives energy kicks from the drain pulses via the gate-drain cap, (C_rss) the latter acting as a coupling capacitor.  The drain side voltage pulse has a low duty cycle and the toroidal coil is not in resonance. 

This circuit you tuned with excellent ingenuity to perform as the scope shot shows and consume just 14uA from 3V reminds me to a Class C oscillator circuit, here is such with a bipolar transistor:

http://www.tpub.com/content/neets/14181/css/14181_80.htm

Yours would be called tuned-gate Hartley oscillator. In the above link, the L2C1 circuit receives energy kicks from the collector side via the coupling coil, L1.

This is the key explanation there: "Once every cycle, the transistor conducts for a short period of time (class C operation) and returns enough energy to the tank to ensure a constant amplitude output signal."

In your case, the MOSFET is able to conduct when the positive voltage peaks across the pulse coil are just over the MOSFET V_th threshold gate source limit, this means when the positive sinus wave goes above 2V (lower limit for the IRF640) with respect to the source i.e. when it comes up from the negative values via zero crossing and climbs up to its peak value, just reaching and passing through the threshold limit, the FET switches ON. 

I agree with you that the MOSFET capacitances contribute to the operation of this oscillator, and at the gate source side the C_iss resonates the pulse coil at 20 kHz.

Thank you for the video demo offering, no need for it. And on the 2 Ohm addition I wrote before: I did not mean it would make it help oscillate but meant to reduce the extra current the lower copper resistance caused because I thought its extra load may explain you failure to find the same sweet spot like you found with the toroidal core. 
Now that I saw you had written on the other forum you had swept through in frequency and did not find any 'sweet' spot with the air core coil, it indicates something is 'wrong'  we do not yet know of.  I 'suspect' you intend to redo the air core coil, I will return to it later how to test its Q if needed.

-----

Comments are welcome from other members too.

Regards,  Gyula