1. What is Thermal Resistance of a Heatsink?

Definition: Thermal resistance (θ) measures how effectively a heatsink transfers heat from a component to the surrounding environment.

Purpose: It helps engineers select appropriate heatsinks for electronic components to prevent overheating.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \theta \) — Thermal resistance (K/W)
• \( h \) — Heat transfer coefficient (W/m²·K)
• \( A \) — Surface area of heatsink (m²)
• \( \eta \) — Fin efficiency (dimensionless, between 0 and 1)

Explanation: Lower thermal resistance means better heat dissipation. The formula shows that increasing any parameter in the denominator reduces thermal resistance.

3. Importance of Thermal Resistance Calculation

Details: Proper thermal management ensures electronic components operate within safe temperature limits, improving reliability and lifespan.

4. Using the Calculator

Tips: Enter the heat transfer coefficient (typically 5-25 W/m²·K for natural convection), surface area, and fin efficiency (default 0.8). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical heat transfer coefficient value?
A: For natural convection, 5-25 W/m²·K; for forced air cooling, 10-100 W/m²·K depending on airflow.

Q2: How do I determine fin efficiency?
A: It depends on fin geometry and material. Simple fins might have η=0.7-0.9, while optimized designs approach 1.

Q3: What's considered a good thermal resistance value?
A: Depends on application. For CPUs, typically 0.1-1.0 K/W; for power electronics, 0.5-5 K/W.

Q4: Does this include contact resistance?
A: No, this calculates only the heatsink resistance. Add interface and junction resistances for total thermal resistance.

Q5: How can I reduce thermal resistance?
A: Increase surface area, improve heat transfer coefficient (better airflow), or use more efficient fin designs.