The resonance of voltage in an AC circuit is a process in which the voltage appearing on a single circuit component is greater than the power supply voltage. This process occurs in a circuit composed of capacitors and inductors connected in series.

In a series resonant device circuit. In order to generate resonance in an AC circuit, certain conditions must be met. Firstly, the reactance of an inductor must be equal to the reactance of a capacitor. In this case, the active resistance of this circuit should be minimized.

Secondly, the natural frequency of the series resonant circuit composed of inductance and capacitance must be consistent with the frequency of the power supply voltage. Then voltage resonance occurs in the circuit. The energy stored in the magnetic field is completely converted into the energy of the electric field in the capacitor, and vice versa.

For an AC voltage source, such a circuit actually becomes a short circuit, and the maximum possible current flows into it. Only limited by the active resistance of the loop. Due to the fact that the reactance of inductance and capacitance becomes zero at the resonant frequency, and energy is not dissipated within them. Unlike active resistors, active resistors release heat according to Lenz Joule's law.

The relationship between current, total reactance, and voltage frequency

When the frequency of the power supply voltage or the parameters of the circuit change, resonance disappears. The voltage distribution across circuit components follows Ohm's law. That is to say, the voltage drop across capacitors and inductors is equal to the current multiplied by their reactance.

In resonance, the voltage across the capacitor or inductor will be Q times greater than the power supply voltage. Q is the quality factor of the circuit, which is the reciprocal of the resonant damping coefficient in the circuit. Therefore, the higher the Q factor of the circuit, the greater the voltage rise will be.

The increase in voltage occurs due to the fact that energy gradually accumulates in the circuit. Resonance in the source voltage excitation circuit. The amplitude will continue to increase until the loss in the resonant circuit becomes equal to the energy given by the signal source.

This process can be illustrated by the example of a person swinging on a swing. A person stands on the ground and provides energy to the swing by pushing it. Swing, gradually swing, increase amplitude. For a moment, the swing of the hand stopped, and the swing moved further due to inertia. However, the increase in swing amplitude is not infinitely limited by gravity and friction. When all forces are balanced, the maximum resonance amplitude will occur.