Views:0 Author:Site Editor Publish Time: 2018-05-15 Origin:Site
We can start with the structure of the film capacitor. The simplest capacitance is made of insulating dielectric. After electrification, the polar plate is electrified to form a voltage (potential difference), but the intermediate is not conductive because of the insulating substance. However, this situation is not in excess of the critical voltage (breakdown voltage) of the capacitor.
We all know that any substance is relatively insulated. When the voltage at both ends of the matter increases to a certain extent, the material can be conductive, which we call the breakdown voltage. Capacitors are no exception. Capacitors are not insulators after breakdown. But in secondary school, such voltage is not seen in the circuit, so it works under breakdown voltage and can be regarded as insulator.
But in AC circuits, the direction of the current varies with time. The process of charging and discharging the film capacitor is time, and at this time, the electric field is formed between the plates, and the electric field is also a function of time. In fact, the current is passed through the formation of the field between the film capacitors. After reading the above, do you understand the principle of film capacitors in AC circuits?