Loss of film capacitors

Film capacitors are capacitors formed by overlapping and winding electrodes made of metal foil or metal compounds and insulating materials. The film thickness of film capacitors is usually from a few microns to tens of microns, so the film material can overlap around the electrodes without being thick.

In the field of electronics, film capacitors, as a common electronic component, are widely used in various circuit systems, playing a key role in filtering, energy storage, coupling, etc.

After using electronic products for a long time, there will be loss problems, and film capacitors are no exception. During the usage process, the loss of film capacitors not only affects their performance, but may also have adverse effects on the stability and reliability of the circuit system.

一、Loss

Loss refers to the loss of signal energy due to various factors during signal transmission. The loss of film capacitors refers to the energy consumed by the capacitor due to heat per unit time under the action of the electric field.

二、Loss categories of film capacitors

There are two types of losses in film capacitors: dielectric losses and electrode losses.

1. Dielectric loss

Dielectric loss refers to the signal energy loss caused by the absorption and scattering of the signal by the insulating material itself.

When a dielectric is exposed to an external electric field, it will generate heat inside. This indicates that part of the electrical energy has been converted into heat and dissipated. The energy consumed by the dielectric due to heat per unit time under the action of an electric field is called the dielectric power loss, or dielectric loss for short.

Dielectric loss not only consumes electrical energy, but also causes the components to heat up and affect their normal operation. If the dielectric loss is large, it will cause the medium to overheat and lead to insulation damage. Therefore, the smaller the dielectric loss, the better.

2. Electrode loss

Electrode loss refers to the energy consumption caused by the passage of signals due to the resistance and inductance of the metal electrode conductor itself.

In high-frequency applications, a cortex will form on the surface of the metal conductor, and a certain amount of energy will be consumed in this cortex. If this energy consumption is too large, the internal temperature of the film capacitor will rise, and the temperature rise will easily lead to a decline in the performance of electronic products.

Therefore, special attention should be paid to reducing electrode losses in high-frequency applications.

Whether it is for film capacitors or electronic products, the smaller the loss, the better.