The self-induced electromotive force in the coil of the inductor always competes with the change in current in the coil. The inductance coil has an obstructive effect on the alternating current, and the magnitude of the resistance is called xl, and the unit is ohm. The relationship between the inductance l and the alternating current frequency f is xl=2πfl, and the inductor can be mainly divided into a high frequency choke coil and a low frequency choke coil.
Tuning and frequency selection
The inductor coil and the capacitor are connected in parallel to form an lc tuned circuit. That is, the natural oscillation frequency f0 of the circuit is equal to the frequency f of the non-AC signal, and the inductive reactance and capacitive reactance of the loop are also equal, so that the electromagnetic energy oscillates back and forth between the inductor and the capacitor, and the resonance phenomenon of the lc loop. At the time of resonance, the inductive reactance and capacitive reactance of the circuit are reversed, the inductance of the total current of the loop is the smallest, and the current is the largest (refers to f=“f0” AC signal). The lc resonant circuit has the function of selecting a frequency and can An AC signal of a frequency f is selected.