Qunio Electronics introduces you: characteristics of electrolytic capacitors
Article Source：QUNIO ELECTRONICS
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issuing time：2019-04-09
1、Aluminum electrolytic capacitors are cheap, can be used for various applications, and are also excellent in electrical performance, which can be said to be inexpensive. Tantalum capacitors have higher prices, but have higher reliability and longer storage life, which is suitable for applications where strict requirements are required.
2、The operating voltage has a certain upper limit. Even if there is a possibility of further raising the upper limit in the future, the potential is limited, but the shortcomings in this respect are not important for the matching of transistors or integrated circuits.
3、The operating voltage has a certain upper limit in the future, the potential is limited, but the shortcomings in this respect are not important for the matching of transistors or integrated circuits.
4、The very high working electric field strength is related to self-healing. For example, in an aluminum electrolytic capacitor with a working voltage of 450V, the thickness of the oxide film is about 0.78 μm, and the working field strength is about 600 kV/mm. Similarly, the product with a low operating voltage has a similar working field strength. Such a field strength is about thirty times that of a paper dielectric capacitor. Solid electrolyte tantalum electrolytic capacitors have a slightly lower field strength, but their values are also of the same order of magnitude. It is precisely because the working field of the electrolytic capacitor is strong that any type of capacitor is large, it is guaranteed to be miniaturized.
5、The capacitance per unit volume is particularly large, that is, the specific capacity is very high. When the operating voltage is lower, the characteristics of this aspect are more prominent, so it is particularly suitable for miniaturization. Since the operating voltage of the electrolytic capacitor can be made relatively low, the capacitor of the same capacity obviously has a higher specific capacity than the low operating voltage. The specific capacity of the working voltage is much larger, so the comparison is not accurate. Therefore, it is also commonly used to express the capacitance and voltage product value per unit volume, that is, microfarad. volt/cm3, where the volume size refers to the external dimension. In other words, it is not only an anode sintered base or a wound core.
6、A large rated capacitor can be obtained, and the electrolytic capacitor can easily obtain a capacitor of several hundred microfarads in a low operating voltage range. In particular, there are no competitors for power supply filtering and AC bypass.
7、The capacity of aluminum electrolytic capacitors is aging, and the reliability of performance is decreasing. This is closely related to the raw materials and process conditions used. Although there are long-life aluminum electrolytic capacitors, in general, there are certain restrictions on its use and storage, especially after long-term storage, and suddenly the upper limit working voltage is the most likely to cause the failure or even blasting of the electrolytic capacitor. In this respect, tantalum capacitors just don't have this problem.
8、Poor insulation. Insulation performance is generally indicated by the magnitude of the leakage current. It can be said that electrolytic capacitors are the worst of all types of capacitors. For example, high-voltage and large-capacity aluminum electrolytic capacitors can have leakage currents of more than 1 mA, and the corresponding insulation resistance is less than 1 megaohm. In this respect, tantalum capacitors are superior to aluminum electrolysis. More, its leakage current is measured in microamps.
9、The loss tangent value is large, and the temperature, frequency, and characteristics are also poor, but the corresponding performance of the tantalum capacitor is better than aluminum electrolysis.
