Raspberry Pi 3, 4, B+ Heat Sinks

Heat sinks are thermal management components designed to dissipate heat from high-power electronic devices and prevent overheating. Their core function is based on the principles of conduction, and convection, transferring heat from a heat source—such as a CPU, power transistor, or BGA package—to the surrounding air or a coolant. By increasing the surface area in contact with cooling media, heat sinks help maintain safe temperature levels and protect component reliability and performance.

Most heat sinks are made of aluminum or copper, materials known for their high thermal conductivity. Aluminum heat sinks are lightweight and cost-effective, ideal for general-purpose cooling solutions, while copper heat sinks offer better conductivity for high-performance or space-constrained applications. Finned and extrusion-style heat sinks use strategically shaped surfaces to maximize exposure to air, enhancing natural or forced convection. Cross-cut designs further improve airflow and thermal dispersion. In advanced applications, heat pipes, liquid cooling, or graphite spreaders may be used to rapidly move heat away from the source. For compact or passive systems, passive heat exchangers rely entirely on natural airflow without the use of fans.

Proper thermal contact between the heat sink and device is critical—thermal interface materials (TIMs) such as thermal paste, pads, or solder are used to fill microscopic gaps and reduce thermal resistance. When selecting a heat sink, consider the thermal output of the component, available space, airflow conditions, and the thermal resistance of the system.