An inductor is an element that can store electrical energy into magnetic energy and store it. The structure of the inductor is similar to a transformer, but with only one winding. In the state where no current is passed through the inductor, when the circuit is turned on, it will try to block the current from flowing through it; in the state where the current is passed, it will try to maintain the current when the circuit is disconnected.

The inductor mainly plays the role of filtering, oscillation, delay, trapping, etc. in the circuit, as well as screening signals, filtering noise, stabilizing current and suppressing electromagnetic interference. The most common function of the inductor in the circuit is to form an LC filter circuit together with the capacitor, which has the function of “through DC, resisting AC”.

1, the symbol of the inductor in the circuit: L

2, the inductance unit: Hen (H), millihen (mH), micro-Heng (μH)

3. The conversion relationship is: 1H=10^3mH=10^6μH=10^9nH

Inductance tolerances are usually expressed in letters, with an error value of 20% in M; an error value of 10% in K; an error value of 5% in J; and an error value of 1% in F. Such as: 100M, that is 10μH, the error is 20%. Inductance error calculation, the maximum allowable deviation of the inductor in the circuit refers to the allowable error of the nominal inductance and the actual inductance of the inductor.

Common chip-type inductor cores are: Mn-Zn ferrite, nickel-zinc ferrite, magnetic powder core, etc.

Classified according to working frequency: divided into high frequency inductor, medium frequency inductor, low frequency inductor

Classified by structure: fixed inductor, adjustable inductor

Classified by function: filter inductor, choke inductor, oscillating inductor, isolation inductor, etc.

Classified by package: chip inductor, plug-in inductor