In the circuit, capacitors is to cut off the DC through alternating current, and it is commonly used in inter-stage coupling, filtering, decoupling, bypass and signal tuning.
A. Filter capacitor is used in the power supply rectifier circuit to filter out the AC component. So that the output of the DC can be more smooth.
B. Decoupling capacitors are used in the amplifier circuit to eliminate self-excitation to ensure the amplifier stable operation.

C. Bypass capacitor is used in a resistance connection and connected to the ends of the resistor to pass the AC signal.

D. Decoupling capacitors are mainly removed from high frequency such as RF signal interference, interference is entered by electromagnetic radiation. In fact, the capacitor near the chip also plays the role of energy storage.

E.The high-frequency switching noise is generated by the active device will propagate along the power line. The main function of the decoupling capacitor is to provide a local DC power supply to the active device to reduce the propagation of the switching noise on the board and to direct the noise to ground.

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