How Tesla coils work

From: http://teslacoil.blogcn.com/diary,10302212.shtml

Tesla coil is a high-voltage generation device that uses circuit resonance for energy conversion. Its working principle is quite different from that of a common transformer. The coupling coefficient K of the common transformer is generally close to 1, so the primary voltage is proportional to the secondary voltage. The coupling coefficient of the Tesla coil is generally less than 0.3, the two-level voltage ratio changes with time and is not linearly related. Let's take a look at the main structure of the Tesla coil:


The main part of the Tesla coil includes: the boost charging circuit, the primary resonance circuit and the secondary circuit. The primary resonance return route consists of the primary coil, the main capacitor, and the firearms. The secondary resonance circuit consists of the secondary coil and the discharge top. The capacitance and inductance values can be determined based on the actual production. But the most important thing is that the resonance frequency of the two circuits must be the same.
The working process of the Tesla coil: the power supply should charge the main capacitor first. When the voltage reaches the discharge threshold value of the firearms, the air in the gap between the firearms is ionically ignited, which is approximately conductive, and the primary resonance circuit is established, transmits energy to the secondary loop through oscillation. The secondary circuit oscillates, receives energy, the voltage of the discharge top cover increases gradually, and ionization the nearby air, 'Look for the discharge path, once it forms a 'passthrough 'with the ground ', the 'lightning 'occurs. If there is no 'lightning lightning', after several weeks (the number of times is mainly related to the coupling coefficient), the primary loop is fully released. Most of the energy is transferred to the secondary road, and some of the energy loss is on the way. The secondary circuit continues to oscillate and the reverse is dominated by the primary circuit. The primary circuit oscillates and the obtained energy is returned to the primary loop in the same way. But another part of the energy consumption is on the way back, so repeatedly (see the schematic diagram) until most of the energy is lost. When the voltage and current at both ends of the ignator are insufficient, the ignator is disconnected, and the external power supply continues to charge the main capacitor. The charging process is much longer than the discharge process, which is about 3 ~ About 10 ms. Therefore, Tesla coil discharge frequency is more than 100 times per second, also makes the visual display of Continuous Discharge effect.
Schematic diagram:

The above image describes the energy transfer process when Tesla coils work. In order to further understand the speed of changes,
The following describes the voltage change process from the perspective of Waveform Simulation:

Further amplification and comparison:

Parameters used to simulate the above waveforms:
L1 = 11uh, C1 = 230nf;
L2 = 60mh, C2 = 42pf;
Active capacitor operating voltage: V = 10 kV
Coupling coefficient: K = 0.14;
Resonance frequency: F = 100 kHz;

Object reference diagram: