What is Resonance?
Resonance is a physical phenomenon in AC circuits. In the ideal (no parasitic resistance) inductance and capacitance series circuit input, plus a sinusoidal voltage source, when the frequency of the power supply is a certain frequency, the capacitive reactance is equal to the inductive reactance, the circuit impedance is zero, and the current can reach infinity. The phenomenon is called series resonance. Similarly, when an ideal LC parallel circuit adds a sinusoidal current source, the total admittance of the circuit is zero, and the voltage on the element is infinite, which is called parallel resonance.