Analysis of the role and working principle of inductors

Circuit design cannot be separated from the inductor, so what is its role? The characteristics of the inductor are exactly opposite to those of the capacitor. It has the characteristics of preventing the passage of alternating current and allowing the smooth passage of direct current. The characteristics of the inductor are to pass DC and resist AC. The higher the frequency, the greater the coil impedance. Inductors often work together with capacitors in circuits to form LC filters, LC oscillators, etc. In addition, people also use the characteristics of inductors to create chokes, transformers, relays, etc.

The function of inductor: pass DC, block AC

Passing DC: The so-called passing DC means that in a DC circuit, the inductor acts like a wire and has no effect.

Resistance to AC: In an AC circuit, the inductor will have impedance, that is, XL, and the current of the entire circuit will become smaller, which will hinder AC to a certain extent.

How does an inductor work?

When alternating current is applied to the inductor coil, its own current changes, causing its own magnetic flux to change and causing induced electromotive force. This phenomenon is called self-inductance. The direction of the self-inductance current always hinders the current change that causes self-inductance. When the alternating current increases, The self-inductance current is in the opposite direction to the alternating current. When the alternating current weakens, the self-inductance current is in the same direction as the alternating current, which has a blocking effect on the alternating current.

1. Self-induction

When a current flows through the coil, a magnetic field is generated around the coil. When the current in the coil changes, the magnetic field around it also changes accordingly. This changed magnetic field can cause the coil itself to generate an induced electromotive force (electromotive force is used to represent the terminal voltage of the ideal power source of the active component).

2. Mutual induction

When two inductor coils are close to each other, the change in the magnetic field of one inductor coil will affect the other inductor coil. This effect is mutual inductance. The size of mutual inductance depends on the degree of coupling between the self-inductance of the inductor coil and the two inductor coils. The component made using this principle is called a mutual inductor.

use:

According to the function of the inductor, the inductor can be divided into oscillating inductor, correction inductor, picture tube deflection inductor, blocking inductor, filter inductor, isolation inductor, compensated inductor, etc.

1. The oscillating inductor is divided into TV line oscillating coils, east-west pincushion correction coils, etc.

2. The deflection inductance of the picture tube is divided into a row deflection coil and a field deflection coil.

3. Choke inductors (also called choke coils) are divided into high-frequency choke coils, low-frequency choke coils, choke coils for electronic ballasts, TV line frequency choke coils and TV airport frequency choke coils, etc.

4. Filter inductors are divided into power supply (power frequency) filter inductors and high-frequency filter inductors. The above is the knowledge required for inductors in circuit design. I believe it will be helpful to everyone.