Inductance coil is one of the electronic components widely used in electrical products, instrumentation and equipment. It is an electronic component that uses the basic elements of the current magnetic effect of the total flow of electricity to carry out work.
Its electrical characteristics are opposite to capacitors. High-frequency data signals will encounter very large frictional resistance when passing through the inductance coil, and it is more difficult to pass smoothly. However, the frictional resistance generated when the low-frequency data signal passes is relatively small, that is, the low-frequency data signal can pass easily. Most of the resistors of the inductance coil to the DC adjustable regulated power supply are zero.
In electronic circuits, inductors are mainly used to carry out safety precautions and filtering for AC data signals or to form a coupling circuit with low-voltage capacitors and resistors. In the circuit design diagram, the inductance coil is indicated by the English alphabet L.
Classification methods of inductors
There are many methods to classify inductors:
According to the wire core classification, it can be divided into hollow core, magnetic core, copper core and iron core.
According to the installation method, it can be divided into a vertical and horizontal inductors.
According to the output power classification, it can be divided into high-frequency, intermediate-frequency and low-frequency inductors.
According to the application field, they are classified by switching power supply circuit filter coil, high frequency filter coil, high frequency choke coil, low frequency choke coil, line deviation and field deviation coil, line fluctuation and line linear calibration coil, local oscillation and High frequency undulating oscillating coil.
According to the adjustable state of inductance, it is classified into fixed and unchangeable inductors, changeable inductors, and inductors that can be slightly adjusted.
According to the winding method and structure of the coil, they are single-sided, multi-layer, with or without skeleton inductors, and variable inductors.
What are the characteristic parameters of inductors?
1. Inductance
In electromagnetism and electronics, inductance is the tendency of an electrical conductor to oppose a change in the electric current flowing through it. The unit of inductance is Henry, and the representative letter is H. The commonly used units are mH and μH.
2. Quality Factors
The quality factor (or Q) of an inductor is the ratio of its inductive reactance to its resistance at a given frequency, and is a measure of its efficiency. Q is the ratio of inductance XL and its equivalent resistance, that is, Q=XL/R. The higher the Q value of the coil, the smaller the loss of the loop.
3. Nominal Current
The nominal current of the inductor coil is the maximum amount of current allowed to pass when the inductor coil is operating under normal conditions. Rated current is the main parameter of high-frequency, low-frequency choke coils and high-power series resonant coils.
4. Distributed Capacitance
The capacitance between turns of the coil, between coil and shield, and between coil and plate is called distributed capacitance. The existence of distributed capacitance reduces the Q value of the coil and makes the stability worse, so the smaller the distributed capacitance of the coil, the better. The distributed capacitance can be reduced by segmental winding.
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