Technology -1

The functions of inductors come from various fields. Why do you say so ? Which kind of fields? The basic functions of inductor winding coil: wave storage, oscillation, delay, wave trapping, etc.

To use a more vivid expression, it is: “passing DC and blocking AC” is firstly used in electronic circuits; the inductor coil has a current-limiting effect on AC, and it can form a high-pass or low-pass oscilloscope, phase-shifting circuit and resonance with a resistor or capacitor. Circuits, etc.; transformers can perform AC coupling, voltage transformation, AC and impedance transformation, etc. Here’s what an inductor does:

1. Blocking effect:

The self-induced electromotive force in the coil always opposes the change in current in the coil. It can be mainly divided into high-frequency choke coils and low-frequency choke coils.

2. Tuning and frequency selection functions:

The inductor and capacitor are connected in parallel to form an LC tuned circuit. If the natural oscillation frequency f0 of the circuit is equal to the frequency f of the non-AC signal, then the inductive reactance and capacitive reactance of the loop are also equal, so the electromagnetic energy oscillates back and forth between the inductor and the capacitor. This is the resonance phenomenon of the LC loop. During resonance, since the inductive reactance and capacitive reactance of the circuit are equal and opposite, the inductive reactance of the total loop current is the smallest and the current is the largest (referring to the AC signal of f=f0). Therefore, the LC resonant circuit has the function of selecting frequency and can An AC signal of a certain frequency f is selected.

1. High-frequency choke coil: High-frequency choke coil is also called high-frequency choke coil. It is used to prevent high-frequency AC current from passing through.

High-frequency choke coils work in high-frequency circuits. They usually use hollow or ferrite high-frequency magnetic cores. The skeleton is made of ceramic materials or plastics. The coils are wound in honeycomb sections or multi-layer flat-wound sections.

2. Low-frequency choke coil: Low-frequency choke coil is also called a low-frequency choke coil. It is used in current circuits, audio circuits or field output circuits. Its function is to prevent low-frequency AC current from passing through.

Generally, low-frequency choke coils used in audio circuits are called audio choke coils, low-frequency choke coils used in field output circuits are called field choke coils, and low-frequency choke coils used in current filter circuits are called field choke coils. It’s called a filter choke.

Low-frequency choke coils generally use “E”-shaped silicon steel cores (commonly known as silicon steel cores), permalloy cores or ferrite cores. In order to prevent magnetic saturation caused by large DC current, appropriate gaps should be left in the core during installation. Air core inductors, magnetic core inductors and copper core inductors are generally medium frequency or high frequency inductors, while iron core inductors are mostly low frequency inductors.

The quality factor of the inductor is related to the DC resistance of the coil wire, the dielectric loss of the coil bobbin, and the loss caused by the core, shield, etc.

In short, at low frequencies, inductors generally exhibit inductive characteristics, which only store energy and filter high frequencies. At the same time, its impedance characteristics are very obvious at high frequencies. There are phenomena such as energy consumption, heat generation, and reduction of perceptual effects. Different inductors have different high-frequency characteristics.