Dielectric strength and dielectric constant of film capacitors

Dielectric strength refers to the ability of a capacitor to withstand a dielectric. It is defined as the large voltage that a unit thickness is subjected to when the sample is broken down, expressed as volts per unit thickness. The greater the dielectric strength of a substance, the better its quality as an insulator. And there is a test for measuring the dielectric strength of the dielectric of the film capacitor. The dielectric strength of the film capacitor is tested by placing the plastic film between two electric powers, and constantly changing the voltage between the electric power from low to high until the plastic The dielectric breakdown of the film occurs such that the voltage applied between the dielectrics during dielectric breakdown is higher than the test voltage.

The dielectric constant of a film capacitor is a measure of the amount of electrical energy stored in a dielectric used in a film capacitor. It refers to the ratio of the capacitance between the two plates of the axial film capacitor when the plastic film is used as the dielectric and the capacitance between the same two electrodes with air as the dielectric or vacuum. The dielectric constant is the product of the relative dielectric constant and the dielectric constant in vacuum. If a material with a high dielectric constant is placed in an electric field, the strength of the electric field will drop in the dielectric.

The dielectric constant of a film capacitor represents the degree of dielectricization, that is, the ability of the dielectric to bind to charge. The larger the dielectric constant of the film capacitor, the stronger the ability to bind the charge; the smaller the dielectric constant of the film capacitor, the weaker the capacitor's ability to bind the charge. The dielectric used in the film capacitor has an effect on the capacity of the capacitor, but it should be noted that the same dielectric has the same effect, and different dielectrics have different dielectric constants, and the effects are different. When choosing a film capacitor, you should understand its parameters so that you can select the right capacitor.