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The level of equivalent series ESR ESR is related to the structure of aluminum Electrolytic capacitor, the capacity, voltage, frequency and temperature of aluminum Electrolytic capacitor. The lower the ESR requirements, the better. When the rated voltage is fixed, the larger the capacity, the lower the ESR. When the capacity is fixed, selecting varieties with high rated voltage can reduce ESR. Low frequency ESR is high, high frequency ESR is low, and high temperature can also cause ESR to rise. Many brands of Equivalent series resistance ESR can be found in the specification.
Frequency characteristic of aluminum Electrolytic capacitor: with the increase of frequency, the capacitance of general Electrolytic capacitor presents the law of decline.
The energy consumed by aluminum Electrolytic capacitor due to heating in unit time under the action of electric field is called loss. All types of capacitors have specified allowable loss values within a certain frequency range. The loss of capacitors is mainly caused by dielectric loss, conductivity loss, and the resistance of all metal parts of the capacitor. Under the action of DC electric field, the loss of Electrolytic capacitor exists in the form of leakage conduction loss, which is generally small. Under the action of alternating electric field, the loss of capacitor is not only related to leakage conduction, but also related to the periodic polarization establishment process.
Ripple current of aluminum Electrolytic capacitor: Ripple current is a very important parameter for the filter circuit of stone machine. The higher the ripple current, the better. Its height is related to the working frequency, with the higher the frequency, the greater the ripple current, and the lower the frequency, the smaller the ripple current. The traditional belief is that we need to have a high ripple current at low frequencies in order to achieve good high current discharge characteristics, making the low frequencies more robust, full, and elastic, as well as good control and driving characteristics; In fact, the high ripple current at high frequencies also greatly contributes to the positive sound quality, allowing for better extension and reduced roughness at high frequencies.
The leakage current of aluminum Electrolytic capacitor is due to the physical structure. Needless to say, the smaller the leakage current, the better. The higher the capacity of Electrolytic capacitor, the greater the leakage current; Reducing the working voltage can reduce the leakage current. Conversely, choosing higher voltage resistant varieties will also help reduce leakage current. Combining the two parameters above, prioritizing the selection of high pressure resistant varieties under the same conditions is indeed a simple and feasible good method; Reduce internal resistance, reduce leakage current, reduce loss angle, and increase service life. There are really many benefits, but the price will be higher. It is said that when the Electrolytic capacitor works at a voltage far lower than the rated working voltage, the depolarization between the electrode and the electrolyte cannot be effectively maintained, which will lead to the polarization of the Electrolytic capacitor, reducing the ripple current, increasing the ESR, and thus early aging. However, the premise of this statement is that it is "much lower than the rated working voltage". Based on some long-term practical experience, it is reasonable to choose about 2/3 of the nominal value of the rated working voltage as the normal working voltage. In spare time, the leakage current of Electrolytic capacitor can be roughly estimated. Charge the Electrolytic capacitor with the same capacity according to the rated withstand voltage, and then test the voltage drop at both ends of the Electrolytic capacitor after it is placed for a period of time. The less the voltage drop, the smaller the leakage current.
The nominal parameters of aluminum Electrolytic capacitor are the values listed on the shell of Electrolytic capacitor ① electrostatic capacity, expressed in uF. ② The working voltage, abbreviated as WV, should be the nominal safe value, which means that in the application circuit, it should not exceed this nominal voltage Temperature: Most common ones are 85 degrees and 105 degrees. Under high temperature conditions (such as pure Class A power amplifiers), a 105 degree nominal should be preferred. In general, selecting a high temperature coefficient also has a positive impact on improving the performance of other parameters.