The role of capacitors in circuits: In DC circuits, capacitors are equivalent to circuit breakers. A capacitor is a device that can store charges and is also one of the most commonly used electronic components.

Capacitors, commonly abbreviated as capacitors, have the ability to hold charges and are represented by the letter C. Definition 1: A capacitor, as the name suggests, is a container for storing electricity and a device that holds charges. English name: capacitor.

Capacitors are one of the widely used electronic components in electronic devices, widely used in circuit isolation, coupling, bypass, filtering, tuning loop, energy conversion, control, and other aspects. Definition 2: Capacitor, any two conductors (including wires) that are insulated from each other and closely spaced together form a capacitor.

A capacitor is different from a capacitor. Capacitance is the basic physical quantity, symbol C, and unit F (farad).

General formula C=Q/U Special formula for parallel plate capacitors: Electric field strength between plates E=U/d, capacitor capacitance determination formula C= ε S/4πkd。

With the rapid development of electronic information technology, the upgrading of digital electronic products is faster and faster. The production and sales of consumer electronics, mainly flat screen TVs (LCD and PDP), laptops, digital cameras and other products, continue to grow, driving the growth of the capacitor industry.

The process of causing a charged capacitor to lose its charge (releasing charge and energy) is called discharge. For example, if a wire is used to connect the two poles of a capacitor, the charges on the two poles will neutralize each other, and the capacitor will release charges and electrical energy.

After discharge, the electric field between the two plates of the capacitor disappears and electrical energy is converted into other forms of energy. In general electronic circuits, capacitors are commonly used to achieve bypass, coupling, filtering, oscillation, phase shift, and waveform transformation, all of which are the evolution of their charging and discharging functions.

This starts with the structure of the capacitor. The simplest capacitor is composed of two end plates and an insulating dielectric (including air) in the middle. After being electrified, the electrode plate is charged, forming a voltage (potential difference), but due to the insulating material in the middle, the entire capacitor is non-conductive.

However, such a situation occurs without exceeding the critical voltage (breakdown voltage) of the capacitor. We know that any substance is relatively insulated. When the voltage at both ends of the substance increases to a certain extent, the substance can conduct electricity, and we call this voltage the breakdown voltage.

Capacitors are no exception. After a capacitor is broken down, it is no longer an insulator. However, in middle school, such voltage is not visible in circuits, so it works below the breakdown voltage and can be seen as an insulator. However, in AC circuits, the direction of current changes as a function of time.

The process of charging and discharging capacitors takes time, and at this time, a changing electric field is formed between the electrode plates, which is also a function of time. In fact, current flows through capacitors in the form of a field.

In middle school, there is a saying that is called "open AC, resistance DC", which refers to the property of capacitance.