FPC / PCB 工程計算機

PCB 功耗計算器：線路電阻與壓降

依線長、線寬、銅厚、電流與工作溫度，計算 PCB 線路電阻、壓降與功耗。

線路電阻壓降計算器怎麼用

線路電阻與壓降會影響 power path、LED、馬達、感測器與低壓大電流設計。這個工具依線長、線寬、銅厚、電流與銅溫估算 resistance、voltage drop 與 power loss。

Trace resistance and voltage drop matter for power paths, LEDs, motors, sensors and low-voltage high-current circuits. This calculator estimates resistance, voltage drop and power loss from conductor geometry.

Trace resistance, voltage drop and power loss

公式: R = rho x L / A; Vdrop = I x R; P = I x Vdrop = I^2 x R

  • R: conductor resistance.
  • rho: copper resistivity adjusted for temperature.
  • L: trace length.
  • A: cross-sectional area from trace width and copper thickness.
  • Vdrop: voltage drop along the trace.
  • P: power dissipated as heat in the conductor.

公式依據

範例

A 100 mm long, 0.2 mm wide, 35 um copper trace carrying 1 A has roughly 246 mOhm resistance at 20 degC.

輸入欄位

  • Trace length
  • Trace width
  • Copper thickness
  • Current
  • Copper temperature

結果輸出

  • Trace resistance
  • Voltage drop
  • Power loss
  • mV per amp

工程注意事項

  • Long and narrow traces can create meaningful voltage drop even when current capacity appears acceptable.
  • Copper resistance increases with temperature, so hot operating conditions should be reviewed.
  • For dynamic FPC areas, avoid solving voltage drop by abrupt width changes in bend zones.

驗證檢查

  • Voltage drop budget
  • Power loss
  • Thermal rise
  • Current path width

相關製程站

  • 線路設計 - Trace width, spacing, bend-zone routing, differential pair spacing
  • 電測 - Open / short, resistance, voltage drop, impedance coupon

相關計算器

FAQ

Why is this different from trace current capacity?

Current capacity estimates temperature rise. Resistance calculation estimates electrical loss and voltage drop. Both should be checked for power conductors.

Does plating copper reduce resistance?

Yes. Finished copper thickness increases cross-sectional area and reduces resistance, so use finished copper thickness when available.