Views: 5 Author: Site Editor Publish Time: 2015-07-15 Origin: Site
1. The classification and function of capacitors
The electric capacity is made up of two metal electrodes between which is insulating material ( mediator). Depending on the insulating material, the capacitor types can be divided as follows:
Based on construction, the capacitors can be divided as: fixed capacitors, variable capacitors and trimmer capacitors.
Based on insulating material, the capacitors can be divided as: gas dielectric capacitors, liquid dielectric capacitors, inorganic solid dielectric capacitors, organic solid dielectric capacitors and electrolytic capacitors.
Based on polarity, the capacitors can be divided as: polarized capacitors and non-polarized capacitors. What we usually see is electrolytic capacitors.
Capacitors can partition dc capacitance in a circuit, through the role of alternating current (ac), so they are often used for inter-electrode coupling, filtering, decoupling, bypass and signals.
2. The signs of capacity
The signs of capacity can be divided as domestic standard notation and international electronic sign notation, of which the only distinction is the expression of polarized capacity. The domestic expression is a transverse line below an empty basket, while the international expression is a normal capacitor plus a "+" symbol represents positive.
3. The unit of capacity
The basic unit of capacity is F(Farad). Besides there is uF(Microfarad) pF(Picofarad), and another rarely used unit nF(Nanofarad). Due to the huge capacitance of F, the common we use is uF, pF, and nF rather than F. The conversion is as follows:
1 uF =1000 nF =1000000 pF
4． The withstand voltage of capacity unit: V (Volt)
Every capacitor has its withstand voltage, this is an important parameter of capacitors. The nominal withstand voltage of common non-polarized capacitors can be classified as follows:63V, 100V, 160V, 250V, 400V, 600V, 1000V,etc. The withstand voltage of polarized capacitors is lower than that of non-polarized capacitors, and the general nominal withstand voltage as follows:4V, 6.3V, 10V, 16V, 25V, 35V, 50V, 63V, 80V, 100V, 220V, 400V,etc.