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🔌 电压降计算器Voltage Drop Calculator
按导线材料、截面积（mm² 或 AWG）、单程长度、电流和系统电压计算线路压降和末端电压。Voltage drop and end voltage from conductor material, size (mm² or AWG), one-way length, current and system voltage.
使用说明与常见问题How-to & FAQ
「电压降计算器」是什么？What is the Voltage Drop Calculator tool?
按导线材料、截面积（mm² 或 AWG）、单程长度、电流和系统电压计算线路压降和末端电压。Voltage drop and end voltage from conductor material, size (mm² or AWG), one-way length, current and system voltage.
如何使用「电压降计算器」？How do I use the Voltage Drop Calculator tool?
在「电压降计算器」中，填写「导线材料」、「截面积」、「截面单位」、「单程长度 (m)」、「电流 (A)」等参数，结果会随输入实时计算并显示在下方。In the Voltage Drop Calculator: Fill in "Conductor", "Size", "Size unit", "One-way length (m)", "Current (A)"; results are recalculated instantly as you type.
用的是什么电阻率？Which resistivity values are used?
按 20 °C 计：铜 1.724×10⁻⁸ Ω·m，铝 2.82×10⁻⁸ Ω·m；导线发热时电阻会更大，交流大截面线路还有电抗，实际压降可能偏高。At 20 °C: copper 1.724×10⁻⁸ Ω·m, aluminum 2.82×10⁻⁸ Ω·m. Hot conductors have higher resistance and large AC cables add reactance, so real drop can be higher.
单相为什么乘 2？Why multiply by 2 for single-phase?
单相或直流电流要经过去线和回线两根导线，所以按单程长度 × 2 计算；三相平衡负载按 √3 计算线电压降。Single-phase and DC current flows out and back through two conductors (2 × one-way length); balanced three-phase uses √3 for the line-to-line drop.
计算结果可以用于作业或工程吗？Can I use the results for homework or engineering?
「电压降计算器」使用教科书标准公式（公式写在说明和常见问题中），适合学习和估算核对；涉及安全的工程设计请以规范和实测为准。The Voltage Drop Calculator uses standard textbook formulas (given in the description and FAQ), which is good for learning and checking estimates; for safety-critical engineering follow codes and measured values.
「电压降计算器」免费吗？需要注册吗？Is the Voltage Drop Calculator free? Do I need an account?
「电压降计算器」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Voltage Drop Calculator is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.