What is the role of electrolytic capacitor in switching power supply?

The functions of electrolytic capacitors in switching power supplies include bypassing, decoupling, filtering, and energy storage.

1. The bypass capacitor is an energy storage device that provides energy to the local device. It can make the output of the voltage stabilizer uniform and reduce the load demand. Just like a small rechargeable battery, the bypass capacitor can be charged and discharged to the device.
2. Decoupling: specifically refers to the removal of noise on the chip's power pin, which is generated by the work of the chip itself. The configuration of decoupling capacitors can suppress the noise generated by load changes, which is a common practice in the reliability design of printed circuit boards.
3. Filtering: The capacitor converts the voltage change into the current change. The higher the frequency, the greater the peak current, thus buffering the voltage. Filtering is the process of charging and discharging.

Electrolytic capacitor is a kind of capacitor. The metal foil is the positive electrode (aluminum or tantalum), and the metal oxide film (aluminum oxide or tantalum pentoxide) close to the positive electrode is the dielectric. The cathode is made of conductive materials and electrolyte (the electrolyte can be liquid or Solid) and other materials are composed together. Because the electrolyte is the main part of the cathode, the electrolytic capacitor is named after it. At the same time, the positive and negative electrolytic capacitors cannot be connected wrongly. Aluminum electrolytic capacitors can be divided into four categories: lead type aluminum electrolytic capacitors; bullhorn type aluminum electrolytic capacitors; bolt type aluminum electrolytic capacitors; solid aluminum electrolytic capacitors.