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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 +**125**degrees 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.
