Tesla's Bifilar Pancake Coils

[7imix]

Jiffycoil started building bifilar pancake coils with a nice technique that makes them easy to wind.

http://www.energeticforum.com/renewa...tml#post115068



In Tesla's patent 512,340, "Coil for electro-magnets", he says:

I have found that in every coil there exists a certain relation between its self-induction and capacity that permits a current of given frequency and potential to pass through it with no other opposition than that of ohmic resistance, or, in other words, as though it possessed no self-induction.

COIL FOR ELECTRO-MAGNETS - Google Patent Search

These bifilar pancake coils will be useful for many types of circuits discussed here. If we can learn to design and build pancake coils that have no self-induction, we may observe interesting effects that deserve study.

[7imix]

This post by Lamare is the inspiration for this thread, and it contains many links with very useful information about bifilar coils.

http://www.energeticforum.com/renewa...tml#post115135

[electricity]

Old school pancake coil

Has anyone wound a pancake coil with electrically aniso-tropic cotton die electric?.

[Jiffycoil]

Where can you get the wire? It would be interesting to see how it performs.

[kazm]

Where can you get the wire? It would be interesting to see how it performs.

Hi Jiffycoil, this is what lasersaber and the Nathan Stubblefield Earth Battery replicators have been using:

COTTON COVERED Covered Copper Wire
wires.co.uk : Double Cotton Covered Copper Wire

It's interesting to note that Stubblefield used two types of wire (cotton covered copper & iron) which maintain a (seemingly galvanic) potential difference. Tesla refers to the importance of increased potential difference in his patent:

In order to attain my object and to properly increase the capacity of any given coil, I wind it in such a way as to secure a greater difference of potential between it's adjacent turns or convolutions

What I claim as my invention is -
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 the coil a capacity capable of neutralizing its self-inductance, as hereinbefore described.

Was Tesla doing the same?

[electricity]

Wrong material = crappy coil

It's interesting to note that Stubblefield used two types of wire (cotton covered copper & iron) which maintain a (seemingly galvanic) potential difference. Tesla refers to the importance of increased potential difference in his patent:

It's interesting to note that Stubblefield used two types of wire (cotton covered copper & iron) which maintain a (seemingly galvanic) potential difference. Tesla refers to the importance of increased potential difference in his patent:
Was Tesla doing the same?

By Tesla -Delivered before the Institution of Electrical Engineers, London, February 1892.

Good coils may be produced by employing wires covered with several layers of cotton, boiling the coil a long time in pure wax, and cooling under moderate pressure. The advantage of such a coil is that it can be easily handled, but it cannot probably give as satisfactory results as a coil immersed in pure oil. Besides, it seems that the presence of a large body of wax affects the coil disadvantageously, whereas this does not seem to be the case with oil. Perhaps it is because the dielectric losses in the liquid are smaller.

I have tried at first silk and cotton covered wires with oil immersion; but I have been gradually led to use gutta-percha covered wires, which proved most satisfactory. Gutta-percha insulation adds, of course, to the capacity of the coil, and this, especially if the coil be large, is a great disadvantage when extreme frequencies are desired; but, on the other hand, gutta-percha will withstand much more than an equal thickness of oil, and this advantage should be secured at any price. Once the coil has been immersed, it should never be taken out of the oil for more than a few hours, else the gutta-percha will crack up and the coil will not be worth half as much as before. Gutta-percha is probably slowly attacked by the oil, but after an immersion of eight to nine months I have found no ill effects.

May be we're not producing the same result because we are materials are all wrong, synthetic crap=crappy coil . ?

[Jiffycoil]

Has anyone wound a pancake coil with electrically aniso-tropic cotton die electric?.

Yes I have this is a few images of it powered up.


Pancake coil 2 by jiffycoil, on Flickr


pancake coil by jiffycoil, on Flickr


Bi Polar pancake coil by jiffycoil, on Flickr

[SeaMonkey]

As an experiment a "loosely" wound variant of the
Tesla bifilar coil, (6 turns, 8 in diameter) was used
as a Digital TV Loop Antenna.

It has good broadband gain and unusually high directivity.

Very interesting possibilities.

[Jiffycoil]

@SeaMonkey
Great experiment. How far are you from the transmitter?

[nvisser]

Jiffycoil started building bifilar pancake coils with a nice technique that makes them easy to wind.

http://www.energeticforum.com/renewa...tml#post115068
.

Could you please refer to a post number in that thread. The page content differs from country to country.

[sebosfato]

Pancake coils are important due to the asymmetry of electric fields.

The inner turns have less inductance than outside coils.

If you use insulated wire, it acts as a simple coil. If bare copper will behave as a strange device.

As there are two coils bifilar, the electric field of one coil induce movements of electrons on the other coil where induction is lower.

If you make it to self support, without touching anything else than the circuit, it will behave completely different.

Vacuum would be a the perfect insulation mean.

[sebosfato]

This coil would provide a Q factor that increases with voltage applied to it. So if get it into resonance it will become a self oscillating system. By no self induction don't mean that you don't have inductance, the way the coil is show in the drawing you can actually see it.

The fact is that the coils are not subjected by other coils all around fields around them, so only outwards. And if you think of the field it will be ever increasing outward. Than you can also think that if there is a frequency of a certain nature that should be harnessed it would in this coil because the bigger you make it the widest the band of the "antenna" because there is not only one self resonant frequency. _Every turn have a different inductance capacitance configuration... wider band filter with high q

The electric field of the outer turns is bigger than on the inner coils so as its inductance, so electric field takes place and move the electrons by electrostatic induction force... Accelerating the electrons or creating a sort of super conductivity that amplify the electricity flowing on the wire.

A capacitor is needed to resonate with it at the right frequency to achieve the desired effect.

The input circuit must be coupled using flux condensers. and the output can be taken on a secondary coupled to the coil.

This circuit being driven into high voltage operation using only electrostatic forces thru the flux condensers.

[Jiffycoil]

Could you please refer to a post number in that thread. The page content differs from country to country.

Hi, sorry for the delay with an answer. The pancake coils are easy to wind. If you have a winding jig they are even easier. Check out my Flickr link and it shows winding a coil on my homemade winding jig. If winding by hand then you will be the winding jig and it will be a slower go but the results will be the same. In the photos you will see I used sheet rock paper tape as the insulator between winds. For the smaller coils you can use 1/2 inch masking tape or some tape around that size. You want the sticky side facing towards you so the wire will stick to it and help keep it in the center. You can attach the tape to the coil form (plastic tube) with a piece of tape.

Have Fun

[nvisser]

Hi, sorry for the delay with an answer. The pancake coils are easy to wind. If you have a winding jig they are even easier. Check out my Flickr link and it shows winding a coil on my homemade winding jig. If winding by hand then you will be the winding jig and it will be a slower go but the results will be the same. In the photos you will see I used sheet rock paper tape as the insulator between winds. For the smaller coils you can use 1/2 inch masking tape or some tape around that size. You want the sticky side facing towards you so the wire will stick to it and help keep it in the center. You can attach the tape to the coil form (plastic tube) with a piece of tape.

Have Fun

Thank you. Where will I find This: Check out my Flickr link

[SeaMonkey]

@SeaMonkey
Great experiment. How far are you from the transmitter?

I have it attached to my Digital TV "converter box" in
order to receive the broadcast digital stations locally.

The transmitters are anywhere from 10 to 30 miles
distant in several different directions.

This antenna works better than the single loop I had
used previously and better than a folded dipole
configuration as well. Very surprising for such a small
and simple home-made device.

Very sharp nulls when it is pointed in the wrong
direction for certain stations, and very sharp peaks
when pointed in the proper direction.