Views: 5 Author: Site Editor Publish Time: 2024-12-19 Origin: Site
Film capacitors are a common type of capacitor, mainly used in power electronics, audio and high-frequency circuits. They are composed of metallized film or metal foil electrodes and insulating film dielectrics.
Depending on the dielectric material, film capacitors can be divided into different types of film capacitors such as polyethylene capacitors, polypropylene capacitors, and polystyrene capacitors.
Film capacitors have the advantages of high temperature resistance, low loss, good stability and strong self-healing ability, so they are widely used in many electronic devices.
Electronic devices will have some problems after long-term use, such as low battery life, crackling noise, occasional freezing, etc. Film capacitors will also have similar problems.
During long-term use, the capacity of film capacitors gradually decreases, and the gradual decrease in the capacity of film capacitors affects the normal operation of electronic equipment.
For example, the reduction in capacity may lead to problems such as poor filtering, changes in circuit frequency characteristics, and increased power loss. Therefore, it is necessary to understand the reasons for the reduction in film capacitor capacity in order to take measures based on this problem.
According to inspection and data, the possible reasons for the decrease in film capacitor capacity are:
1. Aging Effect
During long-term operation of film capacitors, the dielectric material may undergo physical or chemical changes, resulting in a decrease in the film capacitance value. This aging effect is mainly manifested in the decomposition, oxidation or moisture absorption of the dielectric material.
2. Impact of the working environment
Film capacitors are sensitive to ambient temperature, humidity, and external pressure. In high temperature environments, the dielectric material may undergo thermal decomposition or deformation, resulting in a decrease in the capacity of the film capacitor.
In a high humidity environment, moisture absorption by the dielectric material may cause an increase in capacitor leakage current, thereby affecting the capacity of the film capacitor.
3. Impact of excessive voltage
Film capacitors operating under high voltage or high frequency conditions will accelerate the degradation of dielectric materials, resulting in a decrease in film capacitor capacity. For example, excessively high voltage may cause dielectric material breakdown, forming tiny breakdown points, which gradually reduce the capacity of film capacitors.
4. Production process issues
The production process of film capacitors can also affect the stability of their capacity. For example, uneven film thickness and poor adhesion between electrodes and dielectrics can lead to unstable film capacitor capacity.
The reduction of film capacitor capacity is a common and unavoidable problem. It is necessary to find the factors causing the reduction of film capacitor capacity and take corresponding measures to ensure the normal operation of electronic equipment.