Definition of Ceramic Capacitor
Ceramic capacitor (ceramic capacitor; ceramic condenser) is also called porcelain dielectric capacitor or monolithic capacitor. It is well understood that the ceramic material with high dielectric constant and low loss is used as dielectric, and the silver layer is sprayed on both sides of the ceramic substrate, then the silver film is fired at high temperature as electrode and soldered on the lead, and the outer surface is coated with protective magnetic paint or encapsulated with epoxy resin; its capacity is determined by the area and thickness of the ceramic piece. Its voltage resistance is determined by the thickness of the ceramic. Its shape is mostly circular, but there are also tube-shaped and round shapes. It is usually blue in color, followed by yellow, brown, etc. Its characteristics are small size, good heat resistance, low loss, high insulation resistance, small capacity, and suitable for high frequency circuits.
Types of ceramic capacitors
1、Distinguished by voltage resistance: high-voltage porcelain dielectric capacitors (above 1KVDC), low-voltage porcelain dielectric capacitors (below 500VDC).
2、According to the structure: round chip capacitor, tube capacitor, rectangular capacitor, chip capacitor, core-piercing capacitor, etc.
3、Distinguish according to medium: Class I porcelain dielectric capacitor, Class II porcelain dielectric capacitor
a: Class I porcelain dielectric capacitors: NP0, SL0, COG.
b: Class II dielectric capacitors: X7R, X5R, Y5U, Y5V.
Y5P has the best temperature compensation performance, and the capacitance value variation range is ±10% in the full temperature range.
Y5U has no compensating property for temperature change, and the capacitance value change range is +22%/-56% in the full temperature range.
Y5V indicates operation from -30 to +85 degrees, with deviation of -82% to +22% over the whole temperature range
X5R means working at -55~+85℃, deviation of plus or minus 15% in the whole temperature range
X7R indicates operation from -55 to +125 degrees Celsius, with a deviation of plus or minus 15% over the entire temperature range
X7R capacitors are called temperature stable ceramic capacitors. the capacity of X7R capacitors varies under different voltage and frequency conditions, it also varies with time, it is mainly used in less demanding industrial applications, the main feature is that the capacity can be made larger with the same volume.
Y5V capacitor is a kind of general-purpose capacitor with certain temperature limitation, which has high dielectric coefficient and can easily achieve small volume and large capacity, and its capacity changes more obviously with temperature, but the cost is lower. They are widely used in applications where capacity and loss are not high.
NPO capacitor is one of the most commonly used monolithic ceramic capacitors with temperature compensation characteristics. The temperature drift of capacitor is very small, and it is one of the most stable capacitors in terms of capacity and dielectric loss. It is suitable for oscillator and resonator slot circuit capacitors, and coupling capacitors in high frequency circuits. x7R capacitors are known as temperature stable ceramic capacitors.
Cucab capacitor film

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Difference and application of high frequency capacitors and low frequency capacitors
High frequency ceramic capacitors (Class I porcelain dielectric capacitors): good capacity stability, low dielectric loss, high insulation resistance, but small capacity; mainly used in high frequency circuits and high frequency high voltage circuits in electronic equipment. (such as the secondary output rectification of computer motherboard and switching power supply)
Low-frequency ceramic capacitor (Class II ceramic capacitor): refers to the capacitor with ferroelectric ceramic as dielectric, Class II ceramic capacitor has small volume and large capacity, but poor stability and high loss. It is mainly used for low frequency bypass, straightening, and filter circuit. (such as the filtering of AC power after rectification)
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