1. What is PWB Current Carrying Capacity?

The PWB (Printed Wiring Board) current carrying capacity calculation determines the maximum current a copper trace can safely carry without excessive temperature rise. It's based on the IPC-2221 standard which considers trace width, copper thickness, and allowable temperature rise.

2. How Does the Calculator Work?

The calculator uses the IPC-2221 formula:

Where:

• \( I \) — Maximum current (Amperes)
• \( k \) — Constant (0.024 for external layers)
• \( \Delta T \) — Temperature rise (°C)
• \( A \) — Cross-sectional area (mm²)

Explanation: The formula calculates the relationship between trace dimensions, temperature rise, and maximum current capacity based on empirical data.

3. Importance of Current Calculation

Details: Proper current capacity calculation is crucial for preventing trace overheating, ensuring signal integrity, and maintaining board reliability in electronic designs.

4. Using the Calculator

Tips: Enter trace width in mm, copper thickness in ounces, and desired maximum temperature rise in °C. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between internal and external traces?
A: External traces have better heat dissipation, resulting in higher current capacity compared to internal traces of the same dimensions.

Q2: How does copper thickness affect current capacity?
A: Thicker copper increases the cross-sectional area, allowing higher current capacity for the same temperature rise.

Q3: What is a typical temperature rise limit?
A: Most designs use 10-20°C temperature rise as a safe limit, though specific applications may have different requirements.

Q4: Are there limitations to this calculation?
A: This formula assumes standard environmental conditions and doesn't account for adjacent traces, board material, or high-frequency effects.

Q5: Should I add safety margins?
A: Yes, it's recommended to add at least 20% safety margin to calculated values for reliable operation.