There will be a letter sign at the end of the charging line to represent the supplier (the supplier signs are F, L, E and None), and there will be no letter sign for the fast charging line produced before February 2005. The charger is a charging device with high frequency power supply technology and advanced intelligent dynamic adjustment charging technology. Charger can be divided into power frequency machine and high frequency machine according to the working frequency of the designed circuit. The power frequency machine is designed based on the traditional analog circuit principle. Internal power devices (such as transformers, inductors, capacitors, etc. ) is larger, generally less noise during heavy load operation. However, the machine has stronger resistance, reliability and stability than the high frequency machine in the harsh power grid environment.