1. What is a PCB Current Carrying Capacity Calculator?

Definition: This calculator estimates the maximum current a PCB trace can safely carry based on temperature rise, trace cross-sectional area, and material properties.

Purpose: It helps electrical engineers and PCB designers ensure their traces can handle required currents without excessive heating.

2. How Does the Calculator Work?

The calculator uses the IPC-2221 formula:

Where:

• \( I \) — Current carrying capacity (amps)
• \( \Delta T \) — Temperature rise above ambient (°C)
• \( A \) — Cross-sectional area of trace (m²)
• \( k \) — Material constant (0.048 for outer layers, 0.024 for inner)

Explanation: The formula accounts for heat dissipation through the PCB material and relates current to temperature rise.

3. Importance of Current Calculation

Details: Proper current estimation prevents trace overheating, ensures reliable operation, and meets safety standards.

4. Using the Calculator

Tips: Enter the desired temperature rise, trace cross-sectional area (width × thickness), and material constant. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical temperature rise limit?
A: Common limits are 10-20°C for general applications, up to 30°C for high-reliability designs.

Q2: How do I calculate cross-sectional area?
A: Multiply trace width (in meters) by copper thickness (typically 35µm or 1oz/ft² = 0.000035m).

Q3: When would I change the material constant?
A: Use 0.048 for external traces, 0.024 for internal traces, or adjust for different PCB materials.

Q4: Does this account for multiple traces?
A: No, this calculates for a single trace. For multiple traces, consider thermal coupling effects.

Q5: What about high-frequency effects?
A: This calculator is for DC/low-frequency. For RF applications, consider skin effect and additional losses.