PCB Trace Width Calculator

PCB Trace Width Formula:

\[ Trace\ Width = \frac{I \times k}{\sqrt{\Delta T \times t}} \]

Current (I):

amps

Temperature Rise (ΔT):

°C

Copper Thickness (t):

oz/ft²

K Factor:

unitless

Trace Width:

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1. What is PCB Trace Width Calculation?

PCB trace width calculation determines the appropriate width of copper traces on printed circuit boards to safely carry specified currents without excessive temperature rise. This is crucial for PCB design reliability and safety.

2. How Does the Calculator Work?

The calculator uses the PCB trace width formula:

\[ Trace\ Width = \frac{I \times k}{\sqrt{\Delta T \times t}} \]

Where:

\( Trace\ Width \) — PCB trace width in mils
\( I \) — Current in amps
\( k \) — Empirical constant (typically 0.048)
\( \Delta T \) — Temperature rise in °C
\( t \) — Copper thickness in oz/ft²

Explanation: This formula calculates the minimum trace width required to carry a given current while limiting temperature rise, based on copper thickness and material properties.

3. Importance of Proper Trace Width

Details: Correct trace width selection prevents overheating, voltage drops, and potential circuit failure. It ensures reliable operation and meets safety standards in PCB design.

4. Using the Calculator

Tips: Enter current in amps, desired temperature rise in °C, copper thickness in oz/ft², and the k factor (default 0.048). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical k factor value?
A: The k factor is typically 0.048 for external layers and 0.024 for internal layers, but may vary based on specific PCB materials and manufacturing processes.

Q2: What temperature rise is acceptable?
A: Typical temperature rises range from 10°C to 20°C for most applications. Higher temperature rises may be acceptable for short-duration currents.

Q3: How does copper thickness affect trace width?
A: Thicker copper allows narrower traces for the same current, as it provides more cross-sectional area for current flow.

Q4: Are there limitations to this calculation?
A: This calculation assumes uniform current distribution and doesn't account for high-frequency effects, via connections, or adjacent trace heating.

Q5: Should I add safety margins?
A: Yes, it's recommended to add 10-20% safety margin to calculated trace widths for critical applications and manufacturing tolerances.