The function and purpose of inductors

1. The main function of an inductor is to pass DC and resist AC, and it mainly plays a role in filtering, oscillation, delay, and notch in the circuit. Inductive coils have a blocking effect on AC current, and the magnitude of the blocking effect is called inductance XL, measured in ohms. Its relationship with inductance L and AC frequency f is XL=2 π fL, and inductors can be mainly divided into high-frequency and low-frequency resistance coils. Tuning and frequency selection function: The inductance coil and capacitor can be connected in parallel to form an LC tuning circuit. If the natural oscillation frequency f0 of the circuit is equal to the frequency f of the non AC signal, then the inductance and capacitance of the circuit are also equal. Therefore, electromagnetic energy oscillates back and forth in the inductance and capacitance, which is the resonance phenomenon of the LC circuit. During resonance, the inductance and capacitance of the circuit are equivalent and opposite, with the inductance of the total circuit current being the smallest and the current being the largest (referring to an AC signal with f="f0"). The LC resonant circuit has the function of selecting a frequency and can select an AC signal with a certain frequency f.

2. Inductors also have functions such as filtering signals, filtering noise, stabilizing current, and suppressing electromagnetic interference. In electronic devices, it is common to see magnetic rings that form an inductor with connecting cables (the wires in the cable wrap several coils of inductance around the magnetic ring). They are commonly used anti-interference components in electronic circuits, and high-frequency noise has a good shielding effect. Therefore, they are called absorption magnetic rings, usually made of ferrite materials, also known as ferrite magnetic rings (referred to as magnetic rings). The magnetic ring has different impedance characteristics at different frequencies. At low frequencies, the impedance is very small, and as the signal frequency increases, the impedance of the magnetic ring sharply increases.

3. Classification: According to whether the inductance is adjustable, it can be divided into fixed inductance, variable inductance, and fine-tuning inductance. According to whether the inductance has an iron core, it can be divided into hollow inductance and iron core inductance.