1. The blocking effect, the self-inductive electromotive force in the Inductor air core coil always counteracts the current change in the coil. Inductive coils have a blocking effect on AC current. The size of the blocking effect is called inductive reactance xl, and the unit is ohm. Its relationship with the inductance l and the alternating current frequency f is xl = 2πfl, so the inductor can be generally divided into a high-frequency choke coil and a low-frequency choke coil.
2. Tuning and frequency selection
Inductive coils and capacitors can be connected in parallel to form an lc tuning circuit. That is, the natural oscillation frequency f0 of the circuit is equal to the frequency f of the non-AC signal, the inductive and capacitive reactances of the loop are also equal, and the electromagnetic energy can oscillate back and forth between the inductance and capacitance, which causes the resonance phenomenon of the lc loop.