Flat-spiral coil

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Flat Spiral Coils

Fig. 1 & 2. Nichola Tesla's U.S. Patent 512,340 Flat Spiral Coils

See also:


Monofilar Flat Spiral Coil

The flat spiral coil creates a magnetic field with poles above and below the spiral plane. See Figure 1.


Bifilar Flat Spiral Coil

Bifilar refers to double windings, per Figure 2.


If the halves of a flat bifilar spiral coil winding are connected in series, the self-capacitance of the coil, created by neighboring windings, is dramatically reduced, enabling higher frequency resonance. This is explained by Nichola Tesla in his US Patent 512340, Coil for Electromagnets shown in Figure 1-2.


However, if the bifilar coil circuits are wired to create opposing magnetic fields in a reverse-series connection then the resultant inductive load of the coil is decreased proportional to the cancellation of the magnetic fields. Moreover, it is conjectured that the resultant inductive qualities would be dependent upon the electromagnetic configuration of the local environment.


A bifilar spiral coil has been used in SQUID device resonators to map a terrain of magnetic quanta.

Three-phase flat-spiral coil at 90°/180°/90° phases

http://www.tesla-coil-builder.com/FlatSpiralSecondaryTrifilar.htm


Review of Scientific Instruments

The High Frequency Magnetic Field of a Flat Spiral Coil

Retrieved from http://rsi.aip.org/resource/1/rsinak/v4/i10/p542_s1?isAuthorized=no —09:56, 9 February 2011 (MST)


by Sherwood Githens and Otto Stuhlman, The University of North Carolina, Chapel Hill, N. C.
Review of Scientific Instruments / Volume 4 / Issue 10 / CONTRIBUTED ARTICLES (Received 19 July 1933)
The high frequency magnetic field of a flat spiral coil, with an inner opening about one‐fourth the diameter of the coil, was excited by single‐tube tuned plate‐tuned grid and push‐pull oscillators. Frequency range 1500 to 6000 kc/sec. The magnetic fields thus excited were compared with the fields produced by a direct current. The results when a push‐pull oscillator was used to excite the high frequency field showed no apparent difference, except near the far edges lying about 25 cm from the center of the coil, and were independent of frequency.


Unbalanced high frequency excitation showed magnetic field crowded toward the normal axis when filament lead was connected to inner turn of spiral. Field strength across inner diameter was found to be non‐uniform when field was excited by a balanced push‐pull oscillator. Field strength along normal axis of coil diminished more rapidly for a balanced than for unbalanced excitation, independent of method of lead connections and was much smaller for the case of filament lead connected to outer end of spiral.

Uniqueness of the equilibrium of an electron plasma on magnetic surfaces

by Benoit Durand de Gevigney Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
Received 19 November 2010; accepted 9 December 2010; published online 11 January 2011
Abstract
The equilibrium of an electron plasma on magnetic surfaces is governed by a Poisson–Boltzmann equation.[1] The electrons follow a Boltzmann distribution on each surface and the charge density depends exponentially on the electric potential. It is a well-known property that the classical Poisson’s equation, for which the charge density is an independent parameter, possesses a unique solution provided suitable boundary conditions are given. Here we show that the Poisson–Boltzmann equation describing electron plasmas on magnetic surfaces also has a unique solution.[2]
© 2011 American Institute of Physics
Retrieved from http://pop.aip.org/resource/1/phpaen/v18/i1/p014503_s1?isAuthorized=no — 15:42, 10 February 2011 (MST)



  1. The Poisson–Boltzmann equation is a differential equation that describes electrostatic interactions between molecules in ionic solutions.
  2. unique solution: bound to a conservative topology due to the kinematics of the potential in storage.