IEC 60027 IEC 為国际电工委员会的电气技术用字母符号標準分為以下幾個部份 IEC  General 总则 IEC  Telecommunications and electronics 电信和电子学 IEC  Logarithmic and related quantities and their units 对数量和单位 IEC  Symbols for quantities to be used for rotating electrical machines 旋转电机用量值符号 IEC  Control technology 控制技术 IEC  Physiological quantities and units