Quest for Fire (or Radiant Spike)

[Ernst]

Mother Nature just prevented you from preparing 7 eggs for your mother.
That is a good thing, cholesterol wise.

Then you got the poor man's egg-goo-on-your-heavy-Terry-cloth-robe-corner-discount at Ingles.


Ernst.

[OrionLightShip]

Second Best Thing Today

The second best thing that happened today is that I just filled my car at Ingles for $1.69 a gallon.

[OrionLightShip]

what's the best and worst thing that happened in your day!

I thought this was important enough to share.

The best thing that happened today is that I got to cook breakfast for my Mother this morning.

The worst thing is that I dropped all the eggs and salvaged one for Mother. The other six made a huge mess. As I cleaned them up with paper towels and a large bowl; I noticed that the corner of my heavy Terry cloth robe was helping me clean up egg goo. dang it!

[Bob Smith]

Not sure if this will help - from Scherz & Monk's Practical Electronics for Inventors, Third Edition, p. 154. There's actually a mistake in the text on this page, I think (due to two contradictory statements about inductance, capacitance and frequency), but I'll go with the one that lines up with what the page's graphics illustrate:

"When a voltage changes due to ac current passing through a coil, the effect is that of many small capacitors acting in parallel with the inductance of the coil."...

"Inductors exhibit distributed capacitance... Below resonance, the reactance is inductive... Above resonance, the reactance is capacitive and increases with frequency."

In other words, at self-resonant frequency, the coil's impedance is at its highest. As frequency increases above that of self-resonance, the impedance of an inductor drops, and its capacitance rises.
Bob

[OrionLightShip]

BTW, there are enough people here that build and do not think.

Thanks Ernst, I'll certainly remember that quote!

Happy New Year

[Ernst]

I saw that coil of the video and I would be interested in measuring its capacitance and inductance. It is a cylindrical coil that should follow the rule in that document that you were not interested in.
But how to measure this coil's diameter?
How to build it?
I imagine you could make a tool to punch rings from aluminium foil and paper and then stack them up like that man in the video does....
It would take a while, but you'll be rewarded with a magnificent coil!
So if anyone feels like making one....

and a very happy, bright, healthy and prosperous new year!
Ernst.

BTW, there are enough people here that build and do not think.

[OrionLightShip]

No, just one more idea just popped up:

The spike is the result of the coil's inductance. Do you agree?
Now, if you increase the coil's capacitance, you would need more charge to create a certain voltage.
So.... increasing the coil's capacitance would decrease the effect that you search for.

Sounds logical enough?


Ernst.

You might be right about that. I was hoping that if you raised your charge voltage and current to compensate for the increased capacitance, then upon opening the switch...you still have the inductive collapse but the charge stored in the capacitance will also come over with the spike. You only gain something doing this if you believe in magic under the curve. Frankly, I don't know what is under the curve. Nothing has been proven to me yet.

Really, it would be too expensive to build. I think you would have to 3d print thin nylon rings, glue foil to them and then connect them as is shown in the video from the post #2. Way too much effort but it would make one heck of coil.

Since I left the farm and the shed I built behind and sold my printer, I am satisfied (for now) to simply do thought experiments to keep my mind sharp. I know builders on this forum get frustrated with people that think and don't build.

I just can't help it....for now

However, I do share my ideas openly instead of making people play guessing games!

[Ernst]

No, just one more idea just popped up:

The spike is the result of the coil's inductance. Do you agree?
Now, if you increase the coil's capacitance, you would need more charge to create a certain voltage.
So.... increasing the coil's capacitance would decrease the effect that you search for.

Sounds logical enough?


Ernst.

[Ernst]

After all, I have been called a f'ing idiot here at least once.

Happens to the best of us!
All of us, in fact.

You are right about the bifilar coil. I was talking about cylindrical coils and the wire type and pitch in those. Also I think that your interpretation of Tesla's patent is correct, I just wanted to point out his choice of words. I think there is more to it.
But that is not relevant now.

What I want to talk about is the geometry of flat ribbon concentric coils and effect that increased distributed capacitance might have on the inductive spike and how we might utilize that effect to our benefit.

OK, in that case I think my earlier statement that all you need is inductance, would be my contribution to this thread. If you try to form an mental picture of what happens if you increase the distributed capacitance, then I see charges attracting each other between the coil's windings. I think that would slow them down, but that is based on my imagination only .


Ernst.

[OrionLightShip]

>>>>"A coil for electric apparatus the adjacent convolutions of which form parts of the circuit between which there exists a potential difference sufficient to secure in the coil a capacity capable of neutralizing its self-induction, as herein before described".

I believe you have misinterpreted this statement. Capacitive Reactance neutralizes Inductive Reactance is how this should be read. Increasing capacitance does NOT change the inductance of a coil.

If you wind a given amount of wire and find the self-resonant frequency and then rewind it Tesla Bifilar style....you will find a lower self-resonant frequency. This is due to the increased capacitance.

Your earlier statement that added capacitance lowers inductance because the product of the two must balance in the equation to equal the resonant frequency is faulty as well. The frequency changes and is not held constant as you suggested.

As always, I could be completely wrong. After all, I have been called a f'ing idiot here at least once.

It really matters not as I don't want to be sidetracked into a discussion about resonance and its relationship to capacitance and inductance.

What I want to talk about is the geometry of flat ribbon concentric coils and effect that increased distributed capacitance might have on the inductive spike and how we might utilize that effect to our benefit.

[Ernst]

Last sentence on page 2:

The function Ph1() can be used to directly estimate the quarter wave Fres from the h/d ratio and the wirelength:=
Fres = (0.39 * ln(h/d) + 1.19) * 75e6 / wire_length (Hertz)

He does also say that the coils used are all "fairly close wound", but my experience shows that this is not a factor of importance.

Also read Tesla's patent on that bifilar coil claim 1:

A coil for electric apparatus the adjacent convolutions of which form parts of the circuit between which there exists a potential difference sufficient to secure in the coil a capacity capable of neutralizing its self-induction, as hereinbefore described.

You can agree or disagree, but maybe you should do a test to verify it?

I have also tested with coils that are not evenly wound, having a tight winding where capacitance is effective and a less tight winding where induction is effective, or the other way around. See attached picture.
This actually does affect the resonance frequency (by 13%).

Well, as I said, the only way to convince anyone is by putting it to the test!
(I have not tested with flat wire, because that is too difficult to wind on a cylindrical coil)


Ernst.

[OrionLightShip]

While you responded, I reread my post and made a few changes because I thought it was not clear enough. You responded to the less clear version...

see this document.
The winding pitch and wire type are not relevant in calculating the resonance frequency.
So by increasing the capacitance, for example by using flat wire, you decrease the inductance, because the product of these two has to remain the same.


Ernst.

I'm not sure why you brought that document into this discussion??

There is nothing in that document about distributed capacitance or the lowering of inductance.

In fact, the words induction and distributed are not even in the document. That document is all about propagation velocity.

I completely disagree with this statement.

>>>"The winding pitch and wire type are not relevant in calculating the resonance frequency.
So by increasing the capacitance, for example by using flat wire, you decrease the inductance, because the product of these two has to remain the same."

I don't mind being proven wrong at all... perhaps I glossed over the document and you can show me where I missed the important points.

[OrionLightShip]

While you responded, I reread my post and made a few changes because I thought it was not clear enough. You responded to the less clear version...

see this document.
The winding pitch and wire type are not relevant in calculating the resonance frequency.
So by increasing the capacitance, for example by using flat wire, you decrease the inductance, because the product of these two has to remain the same.


Ernst.

hmmmm...

I'll have to give this matter the time and thought it deserves.

I always appreciate a logical discussion

[Ernst]

While you responded, I reread my post and made a few changes because I thought it was not clear enough. You responded to the less clear version...

see this document.
The winding pitch and wire type are not relevant in calculating the resonance frequency.
So by increasing the capacitance, for example by using flat wire, you decrease the inductance, because the product of these two has to remain the same.


Ernst.

[OrionLightShip]

It has experimentally been shown that a coil's self-resonance frequency can be calculated solely using the length/diameter ratio and the wire length. That means that the coil's capacitance and inductance are determined by those values alone.

I think this only true when using round wire of known diameter and the pitch (distance between turns). Certainly using flat wire is going to create larger capacitance. How could it not!

That again, means that by increasing the coil's (distributed) capacitance you decrease its inductance.

Increasing the distributed capacitance would not decrease the inductance. It would increase the capacitive reactance and lower the self resonant frequency. Right?