What is inductance
Inductance, or inductance, is a property of a closed circuit that gives rise to an electromotive force to resist a change in the current passing through the closed circuit. This inductance, called self-inductance, is a property of the closed loop itself. If the current in one closed circuit changes and an electromotive force is induced in another closed circuit, the inductance is called mutual inductance.

The inductance is expressed as u=Ldi/Dt;

Where u is the electromotive force, L is the inductance, I is the current, and t is time.

Inductance is a barrier to alternating current. Under the condition that the ac frequency is fixed, the larger the inductance, the greater the resistance to ac, the smaller the inductance, the smaller the resistance. In addition, in the case of a certain amount of inductance, the higher the frequency of ac, the greater the resistance of inductance to ac, the lower the frequency, the smaller the resistance of inductance to ac. In other words, inductance has the property of preventing ac from passing through and allowing dc to pass through.

The ideal inductance is a pure inductance with no capacitance to allow the ac through, no resistance to allow the dc through, and no loss.

But there is no such inductance. Because of this, inductance is applied. We can use the inductor in the rectifier circuit, because, if we want to get a powerful dc power supply, we must use the rectifier circuit to turn the ac into the dc we need. And because the rectified dc is not pure dc, it contains a lot of ac component, which we do not want, so we can connect the inductor in series in the rectifier circuit, the rectified dc through the inductor, ac component is greatly reduced. The dc component can be transferred to the charge through the resistance of the inductor.

Thus it can be seen that when the alternating current passes through the inductance, the amplitude decreases, and the part of the amplitude decreases does not go anywhere, but is blocked, and also changes.

Because of cost, inductance can’t do is very big, so the inductor’s ability to prevent an alternating current is also limited, direct current from the output inductor has some communication components, components for this part of what we don’t want some communication, we can in the back of the output circuit inductance and another larger capacitance, using the characteristics of dc capacitance can partition, through communication, can get rid of we don’t want to exchange the composition of the filter.

Inductance is a barrier to alternating current. Under the condition that the ac frequency is fixed, the larger the inductance, the greater the resistance to ac, the smaller the inductance, the smaller the resistance. In addition, in the case of a certain amount of inductance, the higher the frequency of ac, the greater the resistance of inductance to ac, the lower the frequency, the smaller the resistance of inductance to ac. In other words, inductance has the property of preventing ac from passing through and allowing dc to pass through.

The ideal inductance is a pure inductance with no capacitance to allow the ac through, no resistance to allow the dc through, and no loss.

But there is no such inductance. Because of this, inductance is applied. We can use the inductor in the rectifier circuit, because, if we want to get a powerful dc power supply, we must use the rectifier circuit to turn the ac into the dc we need. And because the rectified dc is not pure dc, it contains a lot of ac component, which we do not want, so we can connect the inductor in series in the rectifier circuit, the rectified dc through the inductor, ac component is greatly reduced. The dc component can be transferred to the charge through the resistance of the inductor.

Thus it can be seen that when the alternating current passes through the inductance, the amplitude decreases, and the part of the amplitude decreases does not go anywhere, but is blocked, and also changes.

Because of cost, inductance can’t do is very big, so the inductor’s ability to prevent an alternating current is also limited, direct current from the output inductor has some communication components, components for this part of what we don’t want some communication, we can in the back of the output circuit inductance and another larger capacitance, using the characteristics of dc capacitance can partition, through communication, can get rid of we don’t want to exchange the composition of the filter.

The difference between common-mode inductance and differential mode inductance

1. The differential mode current generated between the line and the line of the harassing electromagnetic field causes interference on the load, which is called differential mode interference; The disturbance electromagnetic field generates the common mode current between the line and the ground. The common mode current generates the differential mode voltage on the load and causes interference. This is the interference of the common mode ground loop.

2. The filter inductance to suppress common-mode interference is called common-mode inductance; The filter inductance that suppresses the interference of differential mode is called differential mode inductance.

3. Common-mode inductance is bidirectional; Differential inductance is unidirectional.

4. Common-mode inductance refers to two sets of coils with equal winding number, equal wire diameter and opposite winding direction around the same core. A differential inductor is a coil wound around an iron core.

5. The common mode is that two windings are connected to the zero wire and the live wire respectively. The two windings are both in and out, and the common mode signal is filtered out. The differential mode is a filter inductor connected to the null line and the live line separately.

6. Common-mode signals: two identical signals on the zero line and the fire line, respectively, are coupled to form a circuit; Differential mode signal: the same circuit as the useful signal

7. The characteristics of common-mode inductance are as follows: the core is not afraid of saturation because of the opposite direction of two sets of coils on the same core. The most widely used magnetic core material on the market is high conductivity ferrite material.

Differential – mode inductors are characterized by their high – current applications. Since a coil wound around an iron core saturates the core of the coil when the current flowing into the coil increases, the most commonly used core material on the market is metallic powder core material. Especially iron powder core materials (due to the low price).