Common sense popularization of inductance coils

Inductor coil is also one of the commonly used components in household appliances, instrumentation and other electronic products. It is an electronic component that uses the principle of electromagnetic induction to work. Its electrical characteristics are opposite to those of capacitors, "passing low frequencies and blocking high frequencies". When the high frequency signal passes through the inductive coil, it will encounter great resistance and it is difficult to pass; while the resistance presented by the low frequency signal passing through it is relatively small, that is, the low frequency signal can pass through it more easily. The resistance of the inductive coil to direct current is almost zero.

In electronic circuits, the inductor coil is mainly used to isolate and filter the AC signal or form a resonant circuit with capacitors and resistors.

Classification of Inductor Coils

There are many types of inductor coils, and the classification methods are different.

According to the classification of the core, it can be divided into air core inductance coil, magnetic core inductance coil, iron core inductance coil and copper core inductance coil.

According to the form of installation, it can be divided into vertical and horizontal inductance coils.

According to the working frequency, it can be divided into high frequency inductance coil, intermediate frequency inductance coil and low frequency inductive coil.

According to the classification, it can be divided into power filter coil, high frequency filter coil, high frequency choke coil, low frequency choke coil, line deflection coil, field deflection coil, line oscillation coil, line linear correction coil, local oscillation coil, High frequency oscillating coil.

According to whether the inductance is adjustable, it can be divided into fixed inductance coils, variable inductance coils, and fine-tuned inductance coils.

According to the winding method and its structure classification, it can be divided into single-layer, multi-layer, honeycomb type, skeleton type and non-skeleton type inductance coil.

Inductor model nomenclature

The model of the inductance coil is mainly composed of four parts: main name, feature, type, and difference code:

The first part: the main scale, use L to represent the coil, ZL to represent the choke coil;

The second part: features, with G for high frequency;

The third part: type, with X for small;

Part 4: Distinguishing code, using letters A, B, C, etc.

For example, LGX stands for small plastic high frequency inductor coil.

The main characteristic parameters of the inductor coil

1. Inductance

The inductance refers to the size of the self-inductance ability when the inductance coil passes current.

The unit of inductance is Henry, which is represented by the letter H. The commonly used units are millihenry (mH) and microhenry (μH). 

2. Quality factor

The ratio of the stored energy to the consumed energy in the inductor coil is called the quality factor, also known as the Q value, and its definition formula is:

In the formula, w is the angular frequency of T, L is the inductance of the coil, and R is the total loss resistance of the coil.

3. Rated current

The rated current of the inductance coil refers to the maximum current allowed to pass through the inductance coil during normal operation. Rated current is an important parameter for high-frequency, low-frequency blocking coils and high-power resonant coils.

4. Distributed capacitance

Distributed capacitance refers to the capacitance formed between turns of the coil, that is, the capacitance formed by the air, the insulating layer of the wire, and the skeleton. The sum of these capacitances and the resistance of the inductance coil itself form a resonant circuit, which generates a certain rate of resonance, reduces the stability of the inductance coil inductance, and reduces the Q value. Generally, the distributed capacitance should be reduced. In order to reduce the distributed capacitance of the inductive coil, different control methods are generally used, such as the use of intermediate winding method, honeycomb winding method, etc.

For more information, please contact us at sales@xfullstar.com