1. What is PCB Current Capacity?

The PCB current capacity refers to the maximum amount of current that can safely flow through a copper trace on a printed circuit board without causing excessive heating or damage. It depends on the trace width, copper thickness, and acceptable temperature rise.

2. How Does the Calculator Work?

The calculator uses the basic current capacity equation:

Where:

• \( Width \) — Trace width in mils (1 mil = 0.001 inch)
• \( Thickness \) — Copper thickness in ounces (oz/ft²)
• \( TempFactor \) — Temperature-dependent factor (typically 0.048 A/mil/oz for 10°C rise)

Explanation: The equation calculates the current carrying capacity based on the cross-sectional area of the copper trace and the allowable temperature rise.

3. Importance of Current Capacity Calculation

Details: Proper current capacity calculation ensures PCB reliability by preventing trace overheating, which can lead to thermal damage, increased resistance, or even trace failure.

4. Using the Calculator

Tips: Enter trace width in mils, copper thickness in ounces, and temperature factor (default is 0.048 A/mil/oz for 10°C rise). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical temperature factor value?
A: 0.048 A/mil/oz is common for 10°C temperature rise. For 20°C rise, use about 0.064 A/mil/oz.

Q2: How does copper thickness affect current capacity?
A: Thicker copper (e.g., 2 oz vs 1 oz) doubles the current capacity for the same trace width.

Q3: What are typical PCB trace widths?
A: Common widths range from 5-50 mils for signal traces, and 50-200+ mils for power traces.

Q4: Are there more precise calculation methods?
A: Yes, the IPC-2152 standard provides more detailed calculations considering board material and environment.

Q5: Should I add safety margins?
A: Yes, it's recommended to design with at least 20-50% margin above your maximum expected current.