1. What is a PCB Trace Width Calculator?

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

Purpose: It helps electrical engineers and PCB designers ensure proper current carrying capacity while maintaining safe operating temperatures.

2. How Does the Calculator Work?

The calculator uses the IPC-2221 formula:

Where:

• \( \text{Width} \) — Trace width (mils)
• \( I \) — Current (amps)
• \( \Delta T \) — Temperature rise (°C)
• \( \text{thickness} \) — Copper thickness (oz/ft²)
• \( k \) — Material constant (0.024 for external traces)

Explanation: The formula calculates the minimum trace width needed to carry a given current without exceeding a specified temperature rise.

3. Importance of Proper Trace Width

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

4. Using the Calculator

Tips: Enter the current in amps, desired temperature rise (default 10°C), copper thickness (default 1 oz/ft²), and material constant (default 0.024). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical temperature rise value?
A: 10°C is common, but higher values (20-30°C) may be used for space-constrained designs.

Q2: How does copper thickness affect trace width?
A: Thicker copper allows narrower traces for the same current, as shown by the thickness exponent in the formula.

Q3: When would I change the constant (k) value?
A: Use 0.048 for internal traces or different values for specialized PCB materials.

Q4: What's the difference between mils and mm?
A: 1 mil = 0.0254 mm. This calculator uses mils (1/1000 inch), the standard unit in PCB design.

Q5: Does this account for high-frequency effects?
A: No, this is for DC/low-frequency current. High-speed designs require additional considerations.