1. What is the PCB Current Capacity Equation?

The PCB current capacity equation estimates the maximum current a trace can carry based on its cross-sectional area and allowable temperature rise. It's essential for preventing overheating and ensuring reliable PCB operation.

2. How Does the Calculator Work?

The calculator uses the PCB current capacity equation:

Where:

• \( k \) — Material constant (typically 0.024 for inner layers, 0.048 for outer layers)
• \( \Delta T \) — Temperature rise above ambient (°C)
• \( A \) — Cross-sectional area of the trace (mm²)

Explanation: The equation accounts for the non-linear relationship between current, temperature rise, and trace dimensions.

3. Importance of Current Capacity Calculation

Details: Proper current capacity calculation prevents trace overheating, ensures signal integrity, and maintains PCB reliability over its operational lifetime.

4. Using the Calculator

Tips: Enter the material constant (k), desired temperature rise in °C, and trace cross-sectional area in mm². All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the typical value for k?
A: For standard FR-4 PCBs, k is typically 0.048 for outer layers and 0.024 for inner layers.

Q2: What's a safe temperature rise?
A: Common design limits are 10-20°C for general applications, up to 30°C for high-reliability designs.

Q3: How do I calculate trace area?
A: Area = thickness × width. Standard 1 oz copper is 0.035mm thick (0.7 mils).

Q4: Does this account for ambient temperature?
A: No, ΔT is the rise above ambient. Total temperature = ambient + ΔT.

Q5: Are there limitations to this equation?
A: This is for steady-state conditions. For pulsed currents, other factors come into play.