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.

Click for full size Electricity flows into C1 until a high voltage is seen across G1. When this voltage is high enough, a spark jumps across the gap and allows C1 to discharge into L1 and L2. The voltage "bounces" back and forth at an extremely high rate. When the rate of discharge between C1 and L1 matches the rate of C1 and L2, the two circuits are said to be "in resonance" and the voltage goes up through the roof.

This is the current configuration.

What follows are several different configurations for connecting the components into a working coil. I've tried all of these configurations so far, except "e" and they all work plus, they're all documented in Tesla's Colorado Springs Notes. I've found that changing the configuration demands a dramatic change in the values of C1 and L1 mostly, and sometimes the gap distance as well. I need to do more experiments and document them closer, too.
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Click for full size I haven't tried this one yet because I haven't added a good, solid Earth ground to the lab yet. Hopefully, sometime soon, as I've heard this improves performance by a large margin.

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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Revised: 02/20/02