# Coil Theory

Basic Tesla coil theory involves the property of resonance. When a coil and capacitance
are connected in parallel and briefly pulsed with a voltage, the discharge flows back and
forth between the two at a frequency that depends on the values of both, until disipated by
the resistance of the two. Change the value of either one and the resonant frequency changes.
In a Tesla coil, there are actually two resonant circuits connected together. One, between
the capacitor and the primary, the other between the secondary and the same capacitor. The
voltage is injected by the Neon Sign Transformer, alternating at 60 Hz, (cycles per second).
As the potential
across the gap increases, the charge across the capacitor also increases. When the gap breaks
down, meaning the charge across it is sufficient for electrons to jump across, it sparks and
causes the capacitor to discharge through the primary. This discharge then resonates back
and forth through the primary and to alternate plates of the capacitor until the charge across
the gap builds up
again. Since the secondary is also connected to the capacitor, the secondary also resonates.
When the frequency of the capacitor and primary circuit resonates at the same frequency as
the capacitor and the secondary, the voltages add, and the output goes up through the roof.
The frequencies involved are in the hundreds of thousands of Hz, and the voltages can reach
into the hundred thousands or even millions of volts.

At these potentials and frequencies, some very interesting phenomena can take place.

## Here's a link to an article printed in Exotic Research magazine about
optimization of the Tesla Magnifier Coil system, also called the "extra" coil in his writings.

Making it Work

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Copyright 1999, Steve Dodder

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Revised: 02/20/02