Capacitors are almost indispensable energy storage components in electronic circuits. They have the characteristics of isolating DC, connecting AC and preventing low frequency. It is widely used in coupling, isolation, bypass, filtering, tuning, energy conversion and automatic control circuits.

1、滤波电容：接在直流电源的正、负极之间，以滤除直流电源中不需要的交流成分，使直流电变平滑。一般采用大容量的电解电容器或钽电容，也可以在电路中同时并接其他类型的小容量电容以滤除高频交流电。

1. Filter capacitor: connected between the positive and negative pole of DC power supply to filter out unnecessary AC components in DC power supply and make DC current smooth. Generally, large capacity electrolytic capacitors or tantalum capacitors are used, and other types of small capacity capacitors can also be connected in the circuit to filter out high-frequency alternating current.

2、旁路电容：接在交、直流信号的电路中，将电容并接在电阻两端或由电路的某点跨接到公共电位上，为交流信号或脉冲信号设置一条通路，避免交流信号成分因通过电阻产生压降衰减。

2. Bypass capacitance: connected in the circuit of AC and DC signals, connect the capacitors at both ends of the resistance or connect the capacitance to the common potential at a certain point of the circuit, so as to set a path for AC signal or pulse signal, so as to avoid voltage drop attenuation of AC signal components due to resistance.

3、去耦电容：幷接在放大电路的电源正、负极之间，防止由于电源内阻形成的正反馈而引起的寄生震荡。

3. Decoupling capacitor: connected between the positive and negative sides of the power supply of the amplifier circuit to prevent the parasitic vibration caused by the positive feedback formed by the internal resistance of the power supply.

4、耦合电容：接在交流信号处理电路中，用于连接信号源和信号处理电路或者作两放大器的级间连接，用以隔断直流，让交流信号或脉冲信号通过，使前后级放大电路的直流工作点互不影响。

4. Coupling capacitance: connected in the AC signal processing circuit, it is used to connect the signal source and the signal processing circuit, or as the stage connection between the two amplifiers, so as to cut off the direct current, let the AC signal or pulse signal pass through, so that the DC working points of the front and rear stage amplifier circuits do not affect each other.

5、衬垫电容与谐振电容：主电容串联的辅助性电容，调整它可使振荡信号频率范围变小，幷能显著地提高低频端的振荡频率。

5. Pad capacitor and resonant capacitor: auxiliary capacitor in series with the main capacitor. Adjusting it can reduce the frequency range of oscillation signal and significantly increase the oscillation frequency at the low frequency end.

6、调谐电容：连接在谐振电路的振荡线圈两端，起到选择振荡频率的作用。

6. Tuning capacitor: connected at both ends of the oscillation coil of the resonant circuit, which plays the role of selecting the oscillation frequency.