Capacitors have many uses, mainly including the following:
DC blocking: Its function is to prevent DC from passing through and allow AC to pass through.
Bypass (decoupling): Provides a low impedance path for certain parallel components in an AC circuit. In electronic circuits, decoupling capacitors and bypass capacitors both play a role in anti-interference, and the name of the capacitor varies depending on its position. For the same circuit, a bypass capacitor filters out high-frequency noise in the input signal and removes high-frequency clutter carried by the preceding stage. Decoupling capacitors, also known as decoupling capacitors, filter out interference from the output signal. We often see decoupling capacitors connected between the power supply and ground, which serve three purposes: first, as storage capacitors for this integrated circuit; The second is to filter out the high-frequency noise generated by the device and cut off its propagation path through the power supply circuit; The third is to prevent the noise carried by the power supply from interfering with the circuit.
Coupling: As a connection between two circuits, it allows AC signals to pass through and be transmitted to the next level circuit.
Filtering: In the power circuit, the rectifier circuit converts AC into pulsating DC, and after the rectifier circuit, a larger capacity electrolytic capacitor is connected. By utilizing its charging and discharging characteristics, the pulsating DC voltage after rectification is transformed into a relatively stable DC voltage. In practice, in order to prevent changes in the supply voltage of various parts of the circuit due to load changes, electrolytic capacitors of tens to hundreds of microfarads are generally connected to the output end of the power supply and the input end of the load power supply. Due to the fact that large capacity electrolytic capacitors generally have inductance, they cannot effectively filter out high-frequency and pulse interference signals. Therefore, a capacitor with a capacity of 0.001-0-0.lpF is connected in parallel at both ends to filter out high-frequency and pulse interference.
Temperature compensation: compensates for the impact of insufficient temperature adaptability of other components to improve the stability of the circuit.
Timing: When capacitors and resistors are used together, the time constant of the circuit is determined.
Tune: Systematically tune circuits related to frequency, such as mobile phones, radios, and televisions.
Rectification: Open or close a semi closed conductor switching element at a predetermined time.
Energy storage: storing electrical energy for release when necessary. For example, camera flash, heating equipment, and so on. (Nowadays, the energy storage level of some capacitors is close to that of lithium batteries, and the energy stored in one capacitor can be used by a mobile phone for a day.)