PCB & Anisotropic Materials

Video topic: why a layered material like a PCB doesn't conduct heat the same way in every direction, and how to compute an effective conductivity for it.

Talking points:

• The scale of the difference — a typical PCB's in-plane thermal conductivity (copper-rich layers, ~20 W/m·K) can be 20x+ higher than its through-plane conductivity (<1 W/m·K) — treating it as one isotropic material is a meaningfully wrong simplification.
• How to compute effective k — through-plane: sum layer thermal resistances in series (like resistors in series). In-plane: treat layers as parallel conductive paths (like resistors in parallel). A clean, teachable electrical-circuit analogy.

Sources:

• Simscale — blog entry (PCB anisotropic conductivity)