How To Wind A Toroid Coil - For Joule Thief, etc.

How to wind a toroid core for a joule thief and other experiments. The 2 basic ways are explained.

From Wikipedia:
Some bifilars have adjacent coils in which the convolutions are arranged so that the potential difference is magnified (i.e., the current flows in same parallel direction). Others are wound so that the current flows in opposite directions. The magnetic field created by one winding is therefore equal and opposite to that created by the other, resulting in a net magnetic field of zero (i.e., neutralizing any negative effects in the coil). In electrical terms, this means that the self-inductance of the coil is zero.

The bifilar coil (more often called the bifilar winding) is used in modern electrical engineering as a means of constructing wire-wound resistors with negligible parasitic self-inductance.[1]

MATERIALS:
1 core (color indicates the frequency range it can work efficiently at)
Wire


INTERESTING LINKS
Air Core: http://www.circuits.dk/calculator_sin...
Resonant Frequency: http://www.deephaven.co.uk/lc.html


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