天线长度计算器 — 公式
## PCB Via Current Capacity
### Approach
A via is a hollow copper cylinder. Its cross-section is:
**A = pi x D x t_plating**
Apply the IPC-2221 trace formula to this cross-section to estimate current capacity. For high current, use multiple vias in parallel.
### Approach
A via is a hollow copper cylinder. Its cross-section is:
**A = pi x D x t_plating**
Apply the IPC-2221 trace formula to this cross-section to estimate current capacity. For high current, use multiple vias in parallel.
计算示例
0.6 mm diameter via, 25 um plating, 1.6 mm board, 10C rise.
- Circumference = pi x 0.6 / 0.0254 = 74.2 mils
- Plating = 25 / 25.4 = 0.984 mils
- Area = 74.2 x 0.984 = 73.0 mils^2
- Current = 0.048 x 10^0.44 x 73^0.725 = ~2.8 A