1. What is a PCB Trace Width Calculator?

Definition: This calculator determines the appropriate width for PCB traces based on current, temperature rise, copper thickness, and trace location.

Purpose: It helps electronics designers ensure proper current carrying capacity while maintaining acceptable temperature rise in PCB traces.

2. How Does the Calculator Work?

The calculator uses the IPC-2221 formula:

Where:

• \( Width \) — Trace width (mils)
• \( I \) — Current (amps)
• \( \Delta T \) — Temperature rise (°C)
• \( thickness \) — Copper thickness (oz/ft²)
• \( k \) — Constant (0.048 for external, 0.024 for internal traces)

Explanation: The formula calculates the minimum trace width needed to carry a given current while limiting temperature rise, accounting for copper thickness and trace location.

3. Importance of Proper Trace Width

Details: Correct trace width prevents overheating, ensures reliable current capacity, and maintains signal integrity in PCB designs.

4. Using the Calculator

Tips: Enter the expected current, acceptable temperature rise (default 10°C), copper thickness (default 1 oz/ft²), and select trace location.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between internal and external traces?
A: External traces dissipate heat better (higher k value) than internal traces sandwiched between board layers.

Q2: What temperature rise should I use?
A: 10°C is common for general designs, but high-reliability applications may require lower values.

Q3: How does copper thickness affect the result?
A: Thicker copper allows narrower traces for the same current, as shown by the negative exponent.

Q4: What units does this calculator use?
A: All inputs/outputs are in standard PCB units: amps, °C, oz/ft², and mils (1 mil = 0.001 inch).

Q5: Should I add margin to the calculated width?
A: Yes, consider adding 10-20% to the calculated width for design margin and manufacturing tolerances.