Knowing the Function of Capacitor in Circuit from the Name(I)

Capacitors are almost indispensable energy storage components in electronic circuits. They have the characteristics of separating DC, connecting AC and preventing low frequency. It is widely used in coupling, straightening, bypass, filtering, tuning, energy conversion and automatic control circuits. Getting familiar with the meanings of  names of capacitors in different circuits will help us to understand the electronic circuit diagram.

1.The filter capacitor is connected between the positive and negative electrodes of the DC power supply to filter out the unnecessary AC components in the DC power supply and make the DC electricity smooth. Generally large capacity electrolytic capacitors can be used in the circuit and other types of small capacitance can be connected to filter out high frequency alternating current.

2.The decoupling capacitance is connected to the positive and negative poles of the power supply of the amplifier circuit to prevent parasitic oscillation caused by the positive feedback formed by the internal resistance of the power supply.

3.In a circuit of AC and DC signals, the capacitor is connected to the two ends of the resistance or to the common potential by a certain point of the circuit, so as to set up a path for the AC signal or the pulse signal, and avoid voltage drop attenuation of AC signal components through resistance.

4.In an AC signal processing circuit, a coupling capacitor used to connect a signal source to a signal processing circuit or to connect two amplifiers between stages to separate the DC and allow the AC signal or pulse signal to pass through. The DC operating point of the front and rear amplifier circuit is not affected by each other.

5.The tuning capacitor is connected to the two ends of the oscillation coil of the resonant circuit, which plays the role of selecting the oscillation frequency.

6.Adjusts the auxiliary capacitor in series with the main capacitor of the resonant circuit in the pad capacitor so that the frequency range of the oscillating signal becomes smaller, and the frequency of oscillation at the low frequency end can be significantly increased. By appropriately selecting the capacitor of the pad capacitor, the low-end frequency curve can be raised upwards, making it close to the ideal frequency tracking curve.

7. The compensating capacitor is an auxiliary capacitor connected in parallel with the main capacitor of the resonant circuit, and the frequency range of the oscillation signal can be enlarged by adjusting the capacitor.

8.The neutralization capacitor is connected in parallel between the base and the emitter of the triode amplifier to form a negative feedback network to suppress the self-oscillation caused by the capacitance between the triodes.

9.Stabilizing capacitance in the oscillation circuit stabilizes the oscillation frequency.

10.Timing capacitor in the RC time constant circuit is connected in series with the resistor R to determine the capacitance of the charging and discharging time.