During the use of electrolytic capacitors, its service life is a matter of great concern to us. Voltage, current, switching frequency, installation form, and heat dissipation method are all factors that affect the life of electrolytic capacitors. Therefore, in actual use, we need to optimize these factors as much as possible.
Extremely low temperatures, temperature rises in capacitors, excessive voltages, transient voltages, etc. can cause electrolytic capacitors to fail. Temperature rise is the most influential factor on the working life of electrolytic capacitors.
The conductivity of a capacitor is determined by the ionization capacity and viscosity of the electrolyte. When the temperature is lowered, the viscosity of the electrolyte increases, and the ion mobility and conductivity are lowered. Excessive temperature will accelerate the evaporation of the electrolyte. When the amount of electrolyte is reduced to a certain limit, the life of the capacitor is terminated.
Capacitors are easily broken down under over voltage conditions, and surge voltages and transient high voltages are often found in practical applications. The voltage selection of electrolytic capacitors generally requires a secondary derating, which is reasonable to use up to 80% of the rated value.
When the capacitor is charged and discharged,the current will cause energy loss when flowing through the resistor. The voltage change will also cause energy loss when passing through the dielectric,and the energy loss caused by the leakage current. The result of all these losses is the internal temperature of the capacitor. Raise.
The magnitude of the ripple current directly affects the hot spot temperature inside the electrolytic capacitor. Check the manual of the electrolytic capacitor to get the allowable range of ripple current. If it is out of range, it can be solved in parallel.
The ambient temperature of the electrolytic capacitor is also an important factor affecting the service life. In the application, it is necessary to consider the environmental heat dissipation method, the heat dissipation intensity, the distance between the electrolytic capacitor and the heat source, and the installation method of the electrolytic capacitor.
Capacitor should be installed as far as possible from the heating element, otherwise too high temperature will shorten the life of the capacitor. Install the capacitor at the air inlet at high ambient temperatures.
Electrolytic Capacitors If the above factors are considered in the design of the circuit, the service life of the capacitor can still be guaranteed. Can maximize the service life.
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