What are the uses of capacitors?

.DC isolation: its function is to block the passage of DC and allow AC to pass.

.Bypass (decoupling): Provide a low impedance path for certain parallel components in an AC circuit. In electronic circuits, decoupling capacitors and bypass capacitors both play an anti-interference role. The capacitors are called differently depending on their location. For the same circuit, the bypass capacitor takes the high-frequency noise in the input signal as the object to be filtered out, and filters out the high-frequency clutter carried by the previous stage, while the decoupling capacitor, also known as the decoupling capacitor, takes the interference of the output signal as the object to be filtered out. We can often see that a decoupling capacitor is connected between the power supply and the ground. It has three functions: first, it serves as an energy storage capacitor for the integrated circuit; second, it filters out the high-frequency noise generated by the device and cuts off its path for propagation through the power supply circuit; third, it prevents 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 supply circuit, the rectifier circuit converts the AC into pulsating DC, and a large-capacity electrolytic capacitor is connected after the rectifier circuit. By utilizing its charging and discharging characteristics, the rectified pulsating DC voltage becomes a relatively stable DC voltage. In practice, in order to prevent the power supply voltage of each part of the circuit from changing 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 power input end of the load. Since large-capacity electrolytic capacitors generally have a certain inductance and cannot effectively filter out high-frequency and pulse interference signals, a capacitor with a capacity of 0.001--0.1pF is connected in parallel at both ends to filter out high-frequency and pulse interference.

.Temperature compensation: Compensate for the impact of insufficient temperature adaptability of other components to improve circuit stability.

.Timing: Capacitors are used in conjunction with resistors to determine the time constant of a circuit.

.Tuning: Systematic tuning of frequency-dependent circuits, such as mobile phones, radios, and televisions.

.Rectification: Open or close the semi-closed conductor switching element at a predetermined time.

.Energy storage: store electrical energy and release it when necessary. For example, camera flash, heating equipment, etc. (Nowadays, the energy storage level of some capacitors is close to that of lithium batteries. The energy stored in a capacitor can power a mobile phone for a day)