1. What is PCB Current Carrying Capacity?

The PCB current carrying capacity is the maximum electric current a trace can carry without exceeding the specified temperature rise. It depends on the trace cross-sectional area, allowable temperature rise, and material properties.

2. How Does the Calculator Work?

The calculator uses the IPC-2221 standard equation:

Where:

• \( I \) — Current (Amperes)
• \( k \) — Constant (0.048 for outer layers, 0.024 for inner layers)
• \( \Delta T \) — Temperature rise (°C)
• \( A \) — Cross-sectional area (mm²)

Explanation: The equation accounts for the relationship between current, temperature rise, and trace cross-section in PCB design.

3. Importance of Current Calculation

Details: Proper current capacity calculation prevents overheating, ensures reliability, and maintains signal integrity in PCB designs.

4. Using the Calculator

Tips: Enter the constant k (default 0.048 for outer layers), desired temperature rise, and trace cross-sectional area. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between inner and outer layer constants?
A: Outer layers (k=0.048) can carry more current due to better heat dissipation than inner layers (k=0.024).

Q2: What's a typical temperature rise limit?
A: Common limits are 10°C or 20°C, depending on application requirements.

Q3: How do I calculate cross-sectional area?
A: Area = trace width (mm) × copper thickness (mm). For 1 oz copper (0.035mm), 1mm wide trace = 0.035mm².

Q4: Does this account for high frequency effects?
A: No, this is for DC/low frequency. High frequency designs need additional considerations for skin effect.

Q5: What about multiple parallel traces?
A: For parallel traces, calculate each separately but consider thermal coupling in dense layouts.