Ceramic capacitors have a variety of uses, and they play different roles in different circuits.Typical ceramic capacitor applications are divided into four types, namely coupling, decoupling, smoothing, and filter. This will be explained in detail below,let us take a look.
- Coupling of ceramic capacitors
When a ceramic capacitor is used for a coupling function, its DC component will not pass through but only its AC component will be fully utilized. It is used when it is necessary to separate the AC component from the DC + AC component. Because the operating conditions of transistors, ICs and other active components on the circuit are different, it is necessary to set the ideal operating conditions for each circuit before separating the required AC signals.
The so-called coupling means to combine between circuits. As its literal meaning, it can be used in combination between circuits through coupling capacitors.
2.Decoupling of ceramic capacitors
There are capacitance and inductance components in the power line on the circuit. Due to its influence, once the voltage fluctuation of the power line is large, the operation of the circuit will become extremely unstable. In extreme cases, power supply fluctuations will overlap on the signal line and generate false signals.
Therefore, in order to introduce the interference flowing into the power supply to the grounded part, and to provide a stable current for the sudden change of the load current of the IC and other components, a decoupling capacitor will be used.
As the picture shows, even in a state where the interference overlaps, the decoupling capacitor can lead the interference to the grounded portion.
- For smoothing of ceramic capacitors
Smoothing capacitors are used to suppress pulses generated on the power circuit after rectification and smooth the signal so that it is closer to DC. If a smoothing capacitor is inserted after rectification, it can store electricity in the capacitor at high voltage and discharge at low voltage, thereby effectively suppressing voltage fluctuations.
- Filter of ceramic capacitors
By combining capacitors, resistors, and inductors, a filter that passes only signals of a specific frequency can be manufactured. The filter is divided into a low bypass filter that extracts only low-frequency components and a high bypass filter that extracts only high-frequency components, and can be used separately according to the required frequency.