How does a Tesla Coil exactly work? How does a Tesla Coil exactly work? I am currently making a Tesla Coil in school but before I start, I want to know exactly how does a Tesla Coil work? I understand the various electrical components used in it, but what I don't understand is how do those components together work to make something like Tesla Coil.
 A: A Tesla coil is in many ways the same as a transformer and hence if you know the working of one you can understand the working of the other. 
Now in common transformers, the coils are couple tightly, so that a large amount of energy transfers from the primary to secondary. This works well at low voltages, but at high voltages the insulating air gap may suffer a dielectric breakdown, thereby becoming the reason for heavy losses. The Tesla coil avoids this and hence can be used at very high voltages.
A Tesla coil consists of two LC oscillators very loosely coupled to each other.  When a charged capacitor is connected to an inductor an electric current will flow from the capacitor through the inductor creating a magnetic field. When the electric field in the capacitor is exhausted the current stops and the magnetic field collapses. As the magnetic field collapses, it induces a current to flow in the inductor in the opposite direction to the original current. This new current charges the capacitor, creating a new electric field, equal but opposite to the original field. As long as the inductor and capacitor are connected the energy in the system will oscillate between the magnetic field and the electric field as the current constantly reverses. The figure below shows a common schematic of the Tesla coil.

When the switch is open, the cap is charged. Now when the switch is closed, the action discussed earlier will cause a magnetic field to be built up in the primary inductor and this in turn will set up a field in the secondary. Since the secondary has a large amount of turns, this will cause an extremely high E field to be built up thereby resulting in large voltages.
The new coils have some additional components, but this is the very basic working of the Tesla coil with minimal components.
