The basic functions of aluminum electrolytic capacitors in electronic circuits are generally summarized as: through AC, DC resistance, filtering, bypass, coupling and fast charging and discharging, and has the characteristics of small volume, large storage capacity and high cost performance. With the development of modern technology and the continuous improvement of capacitor performance, aluminum electrolytic capacitors have been widely used in consumer electronics, communication products, computer and peripheral products, new energy, automation control, automobile industry, photoelectric products, high-speed railway, aviation and military equipment.

According to the different electrolyte forms, the aluminum electrolytic capacitors can be divided into liquid aluminum electrolytic capacitors and solid-state aluminum electrolytic capacitors; According to the different ways of export, it can be divided into lead type, welding needle type, welding chip, bolt type, patch type and other five kinds. According to the application field, aluminum electrolytic capacitors are divided into consumer, industrial and special application aluminum electrolytic capacitors. Consumer aluminum electrolytic capacitors are mainly used in the consumer markets such as energy saving lighting, television, display, computer and air conditioning; Industrial aluminum electrolytic capacitors are mainly used in industrial and communication power supply, professional frequency converter, numerical control and servo system, wind power generation and automobile industry; Special aluminum electrolytic capacitors are mainly used in military, aerospace and other special fields.

The voltage that the capacitance should bear in the circuit can not exceed its voltage withstand value. In filter circuit, the voltage withstand value of capacitance should not be less than 1.42 times of the AC effective value. When using electrolytic capacitors, pay attention to the negative and negative poles. Different types of capacitors should be selected for different circuits. Mica and high frequency ceramic capacitors can be selected for cleaning vibration circuit, and paper dielectric, polyester, mica, electrolytic capacitance and ceramic capacitance can be selected for DC isolation. Electrolytic capacitance can be selected for filtering, and polyester, paper medium, ceramic and electrolytic capacitance can be selected for bypass. Before installing the capacitor into the circuit, it should check whether it has any short circuit, open circuit and leakage, and check its capacitance value. During installation, the category, capacity, voltage withstand symbols of capacitance shall be easily seen for verification.