Hardware basics---capacitor classification

一、Classification and function of capacitors
        Capacitors are composed of two metal poles with an insulating material (dielectric) sandwiched between them. Due to the different insulating materials, the types of capacitors formed are also different.
According to the structure: fixed capacitor, variable capacitor, fine-tuning capacitor;
Dielectric material: According to the dielectric material, it can be divided into: gas dielectric capacitor, liquid dielectric capacitor, inorganic solid dielectric capacitor, organic solid dielectric capacitor.
According to the polarity, it is divided into polar capacitors and non-polar capacitors. The most common ones we see are electrolytic capacitors.
Capacitance: Capacitors have the function of blocking direct current and passing alternating current in the circuit.（through traffic）, so it is often used forInterstage coupling, filtering, decoupling, bypassing and signal tuning等。

二、unit of capacitance       

The basic unit of capacitance is: F (method), in addition to μF (microfarad), nF (less used) pF (picofarad), because the capacity of capacitor F is very large, we generally see μF , nF, pF units instead of F units.  The specific conversion between them is as follows:  

1F＝1000000μF 

1μF=1000nF=1000 000pF  

三、Capacitor withstand voltage (unit: V)       

A capacitor has its withstand voltage value, which is one of the important parameters of the capacitor.
       The nominal withstand voltage values of ordinary non-polar capacitors are:63V、100V、160V、250V、400V、600V、1000V等；
       The withstand voltage of polar capacitors is relatively lower than that of non-polar capacitors., the general nominal withstand voltage values are: 4V, 6.3V, 10V, 16V, 25V, 35V, 50V, 63V, 80V, 100V, 220V, 400V, etc.