The type of capacitance should first be classified according to the type of medium. It can be divided into inorganic media according to media capacitor Dielectric electricity of agricultural production system container And electrolytic capacitors.
1. Inorganic dielectric capacitor: including familiar ceramics We often see ceramic capacitors on CPUs for capacitors and mica capacitors. Ceramic capacitors have good comprehensive performance and can be applied to very high frequency devices at GHz level, such as CPU/GPU. Of course, its price is also very expensive.
2. Dielectric capacitors of agricultural production system: for example, film capacitors, which are often used on speakers, are relatively accurate and resistant to high temperature and high pressure.
3. Electrolytic capacitor: It is known that aluminum capacitors are actually electrolytic capacitors. If capacitance is an important and irreplaceable component in electronic components, electrolytic capacitors account for half of the total capacitance industry. The annual output of electrolytic capacitors in China is 30 billion, and the average annual growth rate is as high as 30%, accounting for more than 1/3 of the output of electrolytic capacitors in most countries.
The traditional classification of electrolytic capacitors is based on anode materials, such as aluminum, tantalum or niobium. However, this method of judging capacitance performance by anode is out of date. At present, it determines the performance of electrolytic capacitor key It is not the anode, but the electrolyte, that is, the cathode.
According to the classification of cathode materials, electrolytic capacitors can be divided into electrolyte, manganese dioxide, TCNQ agricultural production system semiconductor, solid polymer conductor, etc.
On the right is a simple and incomplete capacitance classification table, which mainly lists some common capacitance types on board equipment. Through this intuitive tree table, you can have an intuitive understanding of capacitance classification and naming methods. The commonly used capacitors are electrolyte capacitor, solid capacitor and tantalum capacitor.
In the eyes of many users, whether the motherboard, graphics card, industrial control board and other products use solid state capacitors determines whether the board is at a higher level. Solid state capacitors have developed rapidly in domestic technology in the past two years, from the original SANYO to many domestic and foreign brands now competing in the world. Solid state capacitors have stepped down from the altar. Many ordinary electronic and digital products use this kind of products in large quantities. The solid state capacitors shown in the figure are similar to the common aluminum electrolytic capacitors, some of which can be replaced. In addition, there is a solid state capacitor, chip shaped, which is used to replace ordinary tantalum capacitors.
Advantages and Disadvantages of Solid State Capacitor
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Advantages of solid state capacitor
First, avoid slurry explosion. Our motherboard will emit heat in normal work. During long-term use (especially overfrequency and overload use), the heat will cause the electrolyte of ordinary capacitors to expand when heated. When overheated to a certain extent, it will burst beyond the boiling point, commonly known as capacitor slurry explosion. In addition, the electrolyte of ordinary capacitor reacts with aluminum oxide, which may also cause slurry explosion when the host is powered on. Because there is no electrolyte in the solid state capacitor, it can avoid these shortcomings without defect and can be used for a long time.
The second is strong stability. The solid aluminum electrolytic capacitor can continue to work stably in high temperature environment, and the use of solid aluminum electrolytic capacitor can directly improve the performance of the motherboard. At the same time, due to its stable impedance in a wide temperature range, it is suitable for Power Supply wave filtering. It can effectively provide stable and abundant power supply, which is particularly important in overclocking. Solid state capacitors can still work normally in high temperature environment and maintain various electrical properties. Its capacitance will not change more than 15% in the whole temperature range, which is obviously superior to ordinary capacitance. At the same time, the capacitance of solid electrolytic capacitor is basically independent of its working voltage, so as to ensure its stable operation in the voltage fluctuation environment.
Third, the service life is longer. The solid aluminum electrolytic capacitor has an extremely long service life (service life exceeds 50 years). It will not be broken down, and there is no need to worry about the drying up of liquid electrolyte and leakage affecting the stability of the motherboard.
The fourth is low ESR and high rated ripple. ESR (Equivalent Series Resistance) refers to the series equivalent resistance, which is a very important indicator of capacitance. The lower the ESR, the faster the capacitor charges and discharges. This performance directly affects the decoupling performance of the microprocessor power supply circuit. In high-frequency circuits, the advantages of the low ESR characteristics of solid electrolytic capacitors are more obvious. The low ESR characteristic at high frequency is the watershed of the performance difference between solid electrolytic capacitor and liquid capacitor. Solid aluminum electrolytic capacitors have very low ESR and very small energy dissipation. The extremely low ESR characteristics of solid state capacitors under high temperature, high frequency and high power operating conditions can fully absorb the high amplitude voltage generated between power lines in the circuit to prevent its interference to the system high stability
The solid aluminum electrolytic capacitor can continue to work stably in high temperature environment, and the use of solid aluminum electrolytic capacitor can directly improve the performance of the motherboard. At the same time, because of its stable impedance in a wide temperature range, it is suitable for power filtering. It can effectively provide stable and abundant power supply, which is particularly important in overclocking.
Solid state capacitors can still work normally in high temperature environment and maintain various electrical properties. Its capacitance does not change more than 15% in the whole temperature range, which is obviously superior to the liquid electrolytic capacitor. At the same time, the capacitance of solid electrolytic capacitor is basically independent of its working voltage, so as to ensure its stable operation in the voltage fluctuation environment.
2. Long service life
The solid aluminum electrolytic capacitor has an extremely long service life (service life exceeds 50 years). Compared with the liquid aluminum electrolytic capacitor, it can be regarded as "longevity". It will not be broken down, and there is no need to worry about the drying up of liquid electrolyte and leakage affecting the stability of the motherboard. Since there are no problems with liquid electrolyte, solid aluminum electrolytic capacitors make the motherboard more stable and reliable.
The solid electrolyte will not evaporate, expand or even burn like the liquid electrolyte in the high heat environment. Even if the temperature of the capacitor exceeds its tolerance limit, the solid electrolyte is only melted, which will not cause the metal shell of the capacitor to burst, so it is very safe.
The working temperature directly affects the life of electrolytic capacitors. The life of solid electrolytic capacitors and liquid electrolytic capacitors is significantly longer under different temperature environments.
3. Low ESR and high rated ripple current
ESR (Equivalent Series Resistance) refers to the series equivalent resistance, which is a very important indicator of capacitance. The lower the ESR, the faster the capacitor charges and discharges. This performance directly affects the decoupling performance of the microprocessor power supply circuit. In high-frequency circuits, the advantages of the low ESR characteristics of solid electrolytic capacitors are more obvious. It can be said that the low ESR characteristic at high frequency is the watershed of the performance difference between solid electrolytic capacitors and liquid capacitors. Solid aluminum electrolytic capacitors have very low ESR and very small energy dissipation. The extremely low ESR characteristics of solid state capacitors under high temperature, high frequency and high power operating conditions can fully absorb the high amplitude voltage generated between power lines in the circuit to prevent its interference to the system.
At present, the power consumption of the CPU is very large, and the main frequency has far exceeded 1GHz. At the same time, the peak current of the CPU has reached 80A or more, and the output filter capacitor is close to the critical point of operation. On the other hand, the CPU uses a variety of working modes, and most of the time it is in the conversion process of working modes. When the CPU changes from a low power consumption state to a full load state, a large amount of energy required for the instant (generally less than 5 milliseconds) switching of this CPU comes from the capacitors in the CPU power supply circuit. At this time, the high-speed charging and discharging characteristics of solid state capacitors can output peak current in an instant to ensure adequate power supply and stable operation of the CPU.
