No matter where the capacitor is used in the field of electronic technology, it is hoped that the components used meet the performance requirements and will not be easily damaged to achieve the purpose of prolonging the service life. In the circuit design, we should have a deeper understanding of the performance of the electrolytic capacitor, so that we have a good idea, do not make the capacitor has been at the peak of the work. Specifically from the following aspects to consider.

1, reduce the ambient temperature

Reduce the ambient temperature, so that the capacitor does not work at the upper limit class temperature, in addition to consider the heat effect of the capacitor itself, which is particularly important for liquid electrolyte type products. If high temperature is generated, the leakage current will increase sharply and the gas will increase, so that the shell is in a state of rapid increase in internal pressure; In addition, high temperature can accelerate the drying of the electrolyte and shorten the life of the product. Therefore, for products with long life requirements, the working temperature should be controlled below 50℃, so that the corresponding life can be improved by about 1 ~ 2 orders of magnitude. For example, a computer capacitor that can work for 20 years at 45 ° C can only work for 1 to 2 years at 85 ° C. If the application is required at the upper class temperature (85 ° C), the temperature of the capacitor core should not exceed 95 ° C, and also depends on the nature of the selected working electrolyte. This high temperature effect is not as severe for solid tantalum capacitors as for aluminum electrolytic capacitors, but it is certainly harmful.

2. Reduce the upper limit of rated voltage

Reducing the upper limit of the rated voltage, that is, reducing the working field strength of the dielectric oxide film, will be applicable to aluminum capacitors. After reducing the load by half, the lifetime of the capacitor can be improved by as much as two orders of magnitude.

In fact, if the aluminum oxide film is damaged and corroded, the repair of the oxidation worship can only be carried out under the highest working voltage, and it is difficult to restore the thickness of the oxide film under the original forming voltage value locally. Therefore, excessive reduction of the working voltage is not the most appropriate measure for the aluminum electrolyzing capacitor.

Comparing the influence of the above two factors, for aluminum capacitors, reducing the operating temperature is the most critical.

3. Control the ripple current value in the work

The main factor causing power consumption and heating temperature rise of electrolyzer capacitor is ripple current (ripple voltage for capacitors with small capacity). Generally, the failure rate and temperature curve is measured under the DC voltage without ripple, only considering the leakage current, and the internal center temperature of the core is almost the same as the ambient temperature. However, in practical applications, the heating caused by the ripple current can raise the core temperature, which can reach tens of degrees Celsius at the highest (the temperature rise of the core depends on the ambient temperature of the capacitor and the control of the ripple current). Therefore, the high ripple current easily causes the core electrolyte to dry up and the capacitor to fail early. At the same time, the long-term ripple current exceeds the specified value, which is also one of the factors leading to the opening of the capacitor explosion-proof valve.

4, avoid frequent surge voltage applied to the capacitor

When the circuit is turned on or off, a transient voltage in the transition state will be generated, generally its value is greater than the working voltage, and correspondingly an impact current will be generated. If the resistance of the power supply and the load are small, the instantaneous current value is quite large, which is easy to cause damage to the oxide film of the electrolyzing capacitor, because the capacitor under the large impact current, It is easy to heat up the weak area of the film to promote the early generation of crystallization and reduce the voltage resistance, so in order to improve the service life, frequent surge voltage should be avoided to apply to the capacitor, especially when the operating voltage is close to the rated voltage.

5, select the capacitor with smaller leakage current value

As a long-life electrolytically used capacitor, in addition to the above 4 points in addition to the consideration of the factors, in the selection of capacitors in the same type of leakage current is particularly small. This indicates that it has a high quality oxide film and a suitable working electrolyte. Once the ambient temperature is higher, the corresponding increase in leakage current is slower. Otherwise, in the case of mutual influence, when the leakage current increases sharply, the internal temperature will rise, in turn, the leakage current will rise again, and deteriorate until the loss of thermal balance and destruction.