Aluminum capacitors are usually used in compact design, but they are known as large loss capacitors, yet their working life can be critical for applications. Just like other capacitors, Aluminum electrolytic capacitors must indicate their voltage and capacitance values, generally the higher the value, the better the product.
In addition, smaller sizes and equivalent series resistors are often required, which can result in higher costs, and these four factors are often interrelated. These numbers are usually found in the specification table, but once the long life factor is added, Things get very complicated, because the working life of the capacitor is related to the working temperature. Normally, the working life is prolonged at a lower temperature, if there is no higher temperature in the working environment. It would be the right decision to choose a device with a lower operating temperature and a longer life. In the normal operating temperature range, every 10 C drop in ambient temperature, the capacitor works. Increasing the voltage to reduce dielectric errors increases the ESR and, in turn, increases the temperature of the capacitor. As a result, the working life is shortened. The decrease in temperature also increases the ESRs, which increases the output voltage ripple and loop gain. In power supply applications, this can cause oscillations and instability.
Aluminum electrolytic capacitors are generally used for low or high frequency filtering and energy storage. These applications require high capacitance and rated voltages. These devices have the advantages of small size and small voltage spike sensitivity. They have a wide range of dimensions that fit most applications. But these advantages are also reflected in price. So capacitors have become one of the most expensive passive devices in power applications-- although aluminum electrolytic capacitors are the cheapest option of all.
The failure reason of electrolytic capacitor is the most common electrolyte itself with time evaporation characteristics, electrical characteristics of the change. The capacitor is made up of two in the middle of a dielectric layer separates the conductive layer, the anode is a piece of the expanded aluminum surface area, and the oxide layer is used as dielectric the electrolyte is a conductive layer. Thus the liquid evaporation problem. Second pieces of aluminum cathode is used to, current to the working electrolyte. The anodic oxidation is used in the manufacturing process to extend the lifetime of the capacitors, to ensure that the use of materials with high purity.
Therefore, we should not only consider the price factor, but also pay attention to the temperature change and the control of the working time in order to reduce the loss and ensure the long life of the electrolytic capacitor.