1. What is the PCB Current Equation?

The PCB current equation estimates the maximum current a trace can carry based on its dimensions 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 equation:

Where:

• \( I \) — Maximum current (amps)
• \( k \) — Empirical constant (typically 0.048)
• \( \Delta T \) — Temperature rise (°C)
• \( W \) — Trace width (mils)
• \( Thick \) — Trace thickness (mils)

Explanation: The equation accounts for the relationship between trace dimensions, temperature rise, and current carrying capacity.

3. Importance of Current Calculation

Details: Proper current calculation prevents trace overheating, voltage drops, and potential PCB failure. It's crucial for power distribution and high-current applications.

4. Using the Calculator

Tips: Enter temperature rise in °C, trace width and thickness in mils (1 mil = 0.001 inch). The default k value of 0.048 works for most applications but can be adjusted.

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 does trace thickness affect current?
A: Thicker traces carry more current but may increase manufacturing costs. Standard thickness is often 1 oz/ft² (1.37 mils).

Q3: What units should I use?
A: The equation uses mils (thousandths of an inch) for width/thickness. 1 mm = 39.37 mils.

Q4: Are there limitations to this equation?
A: This is for external traces. Internal traces typically carry less current. Also consider nearby traces and board material.

Q5: How conservative are these estimates?
A: The equation provides a good starting point but always verify with testing for critical applications.