LED 限流串联电阻计算器
利用 R = (V_s - V_f) / I_f 计算所需的限流电阻阻值、供电电压、LED 正向压降或工作电流。
Required ballast resistance in Ohms
Power rail voltage in Volts
Diode forward voltage in Volts (Red ≈ 2.0V, White/Blue ≈ 3.2V)
Target LED drive current in Amperes (0.02 A = 20 mA)
分步代入计算过程
Because an LED has an exponential diode I-V curve, a series ballast resistor R must drop the excess supply voltage (V_s - V_f) at the desired forward operating current I_f: R = (V_s - V_f) / I_f.
常见参考标准值
150 Ω resistor on 5V rail
91 Ω – 100 Ω resistor on 5V rail
Use ≥ 2× calculated wattage for thermal derating
20 行数值对照表
Series Limiting Resistor (R) · DC Supply Voltage (V_s)
| # | DC Supply Voltage (V) | Series Limiting Resistor (Ω) | Δ % |
|---|---|---|---|
| 01 | 1.5 V | 0 Ω | -100.00% |
| 02 | 2.397 V | 19.852 Ω | -86.77% |
| 03 | 3.2941 V | 64.7039 Ω | -56.86% |
| 04 | 4.1911 V | 109.5559 Ω | -26.96% |
| 05 | 5 V当前 | 150 Ω | 0.00% |
| 06 | 5.9852 V | 199.2599 Ω | +32.84% |
| 07 | 6.8822 V | 244.1118 Ω | +62.74% |
| 08 | 7.7793 V | 288.9638 Ω | +92.64% |
| 09 | 8.6763 V | 333.8158 Ω | +122.54% |
| 10 | 9.5734 V | 378.6678 Ω | +152.45% |
| 11 | 10.4704 V | 423.5197 Ω | +182.35% |
| 12 | 11.3674 V | 468.3717 Ω | +212.25% |
| 13 | 12.2645 V | 513.2237 Ω | +242.15% |
| 14 | 13.1615 V | 558.0757 Ω | +272.05% |
| 15 | 14.0586 V | 602.9276 Ω | +301.95% |
| 16 | 14.9556 V | 647.7796 Ω | +331.85% |
| 17 | 15.8526 V | 692.6316 Ω | +361.75% |
| 18 | 16.7497 V | 737.4836 Ω | +391.66% |
| 19 | 17.6467 V | 782.3355 Ω | +421.56% |
| 20 | 18.5438 V | 827.1875 Ω | +451.46% |
常见问题解答 (FAQ)
如何使用在线 LED 限流串联电阻计算器 工具？+
输入已知参数或拖动滑块，即可在浏览器中实时计算并可视化 LED 限流串联电阻计算器（基于关系式 R = (V_s - V_f) / I_f）。利用 R = (V_s - V_f) / I_f 计算所需的限流电阻阻值、供电电压、LED 正向压降或工作电流。
可以导出或打印 LED 限流串联电阻计算器 的结果吗？+
可以。支持一键复制数据、打印计算工作表或导出高清 SVG、PNG 和 CSV 文件。
我可以清空 LED 限流串联电阻计算器 中的示例数据并从空白状态开始吗？+
可以。点击工具顶部的“清空 / 空白开始”按钮即可重置所有输入项，随时也可一键重新加载示例数据。