10 Common Inductors and Common Effects

Inductors are commonly known as inductors. They are essentially a coil. There are hollow coils and solid coils. Solid coils have cores made of iron cores or other materials. The unit of inductance is "H", referred to as "Heng". In addition, the smaller units are mH and uH, and their conversion method is 1H = 1000mH = 1000000uH.

Inductance is the ratio of alternating magnetic flux generated outside and around the wire when alternating current passes through the wire, and the magnetic flux of the wire and the current that produces this magnetic flux. When DC current passes through the inductor, only fixed magnetic lines appear around it, which will never change with time. However, if AC current passes through the coil, it will show magnetic lines that change with time.

1

Common role

blocking traffic straight

For direct current, the inductance is equivalent to a short circuit; for alternating current, the inductance is a hindrance to it, the higher the frequency of the alternating current, the greater the hindrance of the inductance to it.

Transformer

For us, the most familiar inductor application is the transformer, as shown in the transformer circuit symbol. If the number of turns of the coil on the left is 100 and the number of turns on the right is 50, if the left side is connected with 220V AC, then the voltage induced on the right side is 110V, I .e. "turns ratio = voltage ratio" while the current is completely opposite. If 1A current flows into the left side, 2A current will flow out from the right side, I .e. "turns ratio = inverse ratio of current", because inductance only changes voltage and current, and the power can not be changed, if the voltage and current are proportional is obviously unreasonable.

RL Low Pass Filter

The so-called low-pass filter is: low-frequency signals can pass, and high-frequency signals can not pass, the circuit schematic diagram below. If the input signal is direct current, then the inductor is equivalent to a wire; now it is short-circuited, and the signal will pass through the inductor and output directly without passing through the resistor. If we gradually increase the frequency of the current, the signal passing through the inductor will gradually decrease until it reaches a certain frequency due to the blocking effect of the inductor on the alternating current. When the current above this frequency can no longer pass through, a low-pass filter is formed at this time. This frequency is called the cut-off frequency, and the formula is f = R/(2π L).

RL high-pass filter

The principle of a high-pass filter is similar to that of a low-pass filter, except that the position of the resistor and inductor has changed. If it is direct current, it will flow back through the inductor. At this time, if the frequency is changed, when the frequency gradually increases, due to the blocking effect of the inductor on the alternating current, when the frequency reaches the cut-off frequency, the high-frequency signal does not pass through the inductor, but directly outputs the high-frequency signal we need. The calculation of the cut-off frequency is also f = R/(2πL).

2

Common Inductance

I-shaped inductance

Its predecessor is the flex-type chip inductor, and the I-shaped inductor is their improvement. The baffle can effectively enhance the energy storage capacity, change the direction and size of EMI, and also reduce RDC. It can also be said to be a compromise between the signal communication inductor and the POWER inductor.

The patch type I-shaped inductor is mainly used for several hundred kHz to one or two MHz smaller power switching, such as digital camera LED boost, ADSL... and so on the lower frequency part of the signal processing or POWER purposes, its Q value is 20, 30, as a signal processing is quite suitable;

RDC is lower than flex patch inductance, and is also very easy to use as POWER. Of course, a large I-shaped inductor must be used for POWER.

The biggest disadvantage of the I-shaped inductor is still the open magnetic circuit, EMI problem, in addition, the noise problem is larger than the flex-type chip inductor. I personally think that the I-shaped inductor is definitely not the best structure, and the improvement space is still very large!

color ring inductance

The color ring inductor is the simplest rod-shaped inductor processing, mainly used for signal processing. There is no big difference between itself and the characteristics of rod-shaped inductors, except that some fixed objects and some colors are added to facilitate the resolution of sense values. Because the unit price is very cheap, the volume is not paid attention to at present, and there are still many color ring inductors used in electronic products that can still use plug-ins. Because it is plug-in and too traditional, it is sooner or later to be eliminated by the times.

air core inductance

The hollow inductor is mainly used for signal processing, which is used for resonance, receiving, transmitting.... Wait. Air can be used in very high frequency products, so many products with low variation requirements are still in use, because air is not the best material for fixing the coil. Therefore, the development of more and more stringent product trends is limited!

toroidal coil inductance

Toroidal coil inductance, is a very ideal shape in the theory of inductance, closed magnetic circuit rarely EMI problems. Make full use of the magnetic circuit, easy to calculate, almost all the theoretical benefits of toroidal coil inductance. However, one of the biggest disadvantages is that it is not easy to flex the line, and the process is mostly handled manually.

Now there are many Chinese people, and girls have good eyes and hands. However, who is willing to let young and lively girls waste their youth! Sooner or later, no one is invited! With machines, the competitiveness of the circular flex line still needs to be improved by engineers who do mechanical and electronic control. Although the toroidal coil inductor is an ideal shape in the inductor, it is mainly artificially deflected and treated as a signal. It is less used because of higher requirements. However, the very small toroidal coil inductor is still used in a very large amount and is mainly used in high-frequency and high-sense communication products.

The largest amount of toroidal coil inductance is made of iron powder core, mixed with resin, etc., so that Air gap is evenly distributed inside the iron powder core, and the inductance has certain sensitivity. when we see the word Air gap, we know that it is used on power. Therefore, the iron powder core ring coil inductance is the most commonly used power inductance, IDC can reach more than 20 amperes.

I think the improvement of the loop coil inductance space is very large, may wish to research and development and thinking in this direction.

The advantage of iron powder core ring coil inductance is ring, but the disadvantage is also ring. I said earlier that the user's favorite shape is square, so the ring coil inductance is not the most advantageous under compromise.

chip laminated high frequency inductor

Patch laminated high-frequency inductors are actually hollow inductors with exactly the same characteristics, but they can be miniaturized because they are easy to fix.

Patch laminated high-frequency inductors are compared with hollow inductors, because air is not a good fixture, but the relative permeability of air is one, which is very useful at high frequencies. Therefore, it is not very good to find some good fixtures with a relative permeability of one.

In fact, most of the substances in the world have one permeability. The cheapest one is stone. The material of high-frequency inductor of patch lamination is stone, and stone is silicon! The material of aluminum oxide and so on is also the same intention.

In a word, the purpose of the high-frequency inductor material of the patch laminate is to make it into a laminated patch to facilitate printed circuits. We not only do not want the material of the high-frequency inductor of the patch laminate to have characteristics, but we hope that it has no better characteristics at all, so that the high-frequency inductor characteristics of the patch laminate are completely like hollow coils. And because it can be fixed, the variation is very small. In the process, because of the lamination process, it can be miniaturized as much as possible. Z = 2 * pi * frequency * inductance value, 2 and pi are constants, regardless of them, the same impedance, the higher the frequency, the smaller the representative inductance value can be, the current frequency of communication products is higher and higher, which represents the demand for inductance value is getting smaller and smaller.

The smaller the sensitivity value, the smaller we can make it, not to mention the magnetic material with high permeability, just use air and stone. Therefore, the use of chip laminated high-frequency inductors will be more and more, which is an inevitable trend of human development.

Compared with the patch-type high-frequency inductor, the Q value of the patch-type high-frequency inductor is not high enough, which is the biggest disadvantage, but I can be sure that the Q value of the patch-type high-frequency inductor on the market is definitely not the limit of this product. Therefore, there is still room for improvement. In addition, because the variation requirements of high-frequency products are very strict, the change of material to temperature is also an important reason why Taiwan and China's patch laminated high-frequency inductors cannot strongly confront the Japanese system!

Alas! Those big bosses really don't know what they grew up on, how to say they will listen! Always thinking about the price! Price reduction is only one of the means of competition. Why don't you think about improving your competitiveness from technology!

Finally, because the sense value will be smaller and smaller, the accuracy requirements are getting higher and higher.

The patch laminated high-frequency inductor will replace the patch-type high-frequency inductor. Nanhai Ichiro predicts that in 5 to 10 years, the patch thin-film high-frequency inductor will also replace the patch laminated high-frequency inductor. Research and market direction, to grasp the right ah!

magnetic bar inductance

Magnetic rod inductance is the reinforcement of hollow inductance. The inductance value is proportional to the magnetic permeability. Plug magnetic material into hollow coil, inductance value, Q value... And so on will be greatly increased. I can imagine the benefits myself. If I can't figure them out or don't want to think, I have to change my profession earlier! Magnetic bar inductance is the simplest and most basic inductance. From 30 to 100 years ago, inductance had any application, and its characteristics were the same.

SMD chip power inductor

The SMD chip power inductor mainly emphasizes the energy storage capacity and the LOSS is less.

Core-piercing magnetic beads

Piercer magnetic beads are impedance devices. Inductors are low-pass components that allow low frequencies to pass and block high frequencies.

Patch magnetic beads

Patch beads are the next generation of core beads.

SMD high frequency transformer, plug-in high frequency transformer

high frequency transformer well, generally used for switching power supply.