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In this article i am explaining the differences between different Ceramic capactior dielectric materials like X7R, X5R, X8R, Z5U,Y5V, X7S, C0G. I used to encounter these names X7R and X5R capacitors regularly but never bothered to look at what they are. Recently i took some time to study them realised how important they are and here are the details of what i learnt.

Ceramic capacitors are broadly categorized into 4 classes based on the dielectrics used in them,

* Class 1 * Class 2 * Class 3 * Class 4

Class 3 and Class 4 capacitors are not widely used and hence have not been standardized.

* * *

Class 1 Capacitors :

Class 1 capacitors have following characteristics,

* _Linear temperature coefficient :_ Their capacitance varies linearly with temperature * _No Voltage dependency :_ Their capacitance does not depend on the applied voltage * _No Aging :_ They do not suffer significant aging process due to para electric materials used in manufacturing * _No electrical losses :_ Have significantly low electrical losses compared to Class 2 capacitors * _Used in High Q filters :_ Due to the above properties they are used in applications like resonant circuits, PLL and Oscillators. * _Have high stability and accuracy_

They use a 3 digit notation to indicate the dielectric used in them according to EIA RS-198 standard

C0G

| | |

| | |– Tolerance

| |—- Multiplier

|—— Coeffcient

Look at the below table, (Source : Wikipedia)

Class 2 capacitors are specifications mentioned above are for operation within fixed temperature range of +25 degrees centigrade to +85 degrees centigrade.

* * *

Class 2 Capacitors :

Class 2 capacitors have following characteristics

* _Non-Linear temperature coefficient :_ Their capacitance varies non linearly with temperature * _High Voltage dependency :_ Their capacitance highly depends on the applied voltage * _Suffer Aging :_ They suffer significant aging process due to ferro electric materials used in manufacturing * _High electrical losses :_ Have significantly high electrical losses compared to Class 1 capacitors * _High Permittvity :_ Due to high Permittivity they have high volumetric efficiency * _High Capacitance values :_ Due to high Permittivity large capacitance values can be achieved in small device casings like 0201, 0402, 0603 * _Used in smoothing applications :_ Due to the above properties they are used in applications like bypassing, coupling, decoupling. * _Have low stability and accuracy_

They use a 3 digit notation to indicate the dielectric used in them according to EIA RS-198 standard

X7R

| | |

| | |– Tolerance

| |—- Upper limit

|—— Lower limit

Refer the table below, (Source : Wikipedia)

So according to the above table,

When manufacturer says that this is a X7R capacitor, it means that the capacitor can operate from -55 degrees centigrade to +125degrees centigrade temperature and the capacitance of the capacitor will not vary more or less than 10% from its nominal value specified.

Similarly, When manufacturer says that this is a Y5V capacitor, it means that the capacitor can operate from -30 degrees centigrade to +85 degrees centigrade temperature and the capacitance of the capacitor will not increase more than 22% and not decrease below 82% from its nominal value.

Most commonly used capacitor dielectrics are X7R,X8R,X5R,Y5V,Z5U,X7S.

* * *

Although Class 1 capacitors have more advantages than Class 2 capacitors, I encounter more X7R and X5R capacitors on day to day basis than C0G capacitors.

note/kevin_zhao/test.txt · 最后更改: 2017/11/24 17:12 (外部编辑)