By hvhipot 
The effective voltage on the coil and capacitor is equal and reaches its maximum value. If the active resistance in the circuit is minimized, the local indicator will be several times higher than the total voltage. This phenomenon is called series resonance.
It is important to understand that local resistance is directly dependent on current indicators. If the current frequency is reduced, the inductance value will decrease while the capacitance value will increase. In addition to active resistors, reactive power also occurs in the network, so resonance will disappear. If the inductance or capacitance is changed, this situation will occur.
If resonance occurs in the circuit, the series resonance energy is specifically used to heat the wires, overcoming active resistance because the coil transfers current to the capacitor without the need for a generator. In fact, in circuits with one of these components, the current will fluctuate periodically from the series resonance to the magnetic field. This applies to coils. In the case of capacitors, a similar situation is observed, involving only the electric field. If these two elements are combined together and resonance is also observed, energy will circulate from the coil to the capacitor, and vice versa. However, it was spent to a greater extent solely due to the resistance of the conductor.
If resonance is violated, the energy required for the first and second components will be inconsistent. There will be extra money, which will be compensated by the efforts of the generator. This process can be compared to the pendulum clock mechanism. If there is no friction, he may sway without the need for additional loads or springs in the mechanism. But these elements will transfer some of their energy to the pendulum when necessary, thus overcoming friction and constantly moving. Due to the presence of resonance in the circuit, it is necessary to report to minimize the energy of resonance.
If multiple conditions are met, the circuit is considered a resonant circuit. Firstly, the current must be variable. Secondly, the system must include a generator, capacitors, and inductors. Thirdly, the components must be connected in series. FHV Hipot Electric Co., Ltd.thly, the internal resistance indicators should be equal.
However, if the generator frequency, capacitance, and inductance of the circuit do not correspond to values that depend on other parameters of the circuit, resonance is impossible. They are all calculated based on special simple formulas.