How to go about choosing a HeatSink

Introduction

The performance and durability of electronic equipment is adversely affected by the component’s temperature. The connection between the operating temperatures and the reliability of a silicon semi-conductor gadget shows that the reliability and the life expectancy increases with the reduction of temperatures. Thus, controlling the device’s running temperature effectively brings about reliable performance and durability. This can be achieved by having the devices operate at operating temperatures that are within the design limits of the engineer. To have the running temperatures at the set limits can only be possible if the equipment is fixed with a heat sink device. Therefore, a heat sink is a device that increases the loss of heat from a heat generating surface to a cooler ambient. 

How the Heat Sink Works

The heat sink works by mostly using air as the ambient or the cooling fluid. This is because the heat transfer between the coolant air across the solid surface in the system is not efficient enough. In addition to that, the solid-air interface acts as a great barrier for dissipation of heat. The device now works by increasing the surface area in direct contact with the coolant air thus reducing the barrier. This way, the operating temperature is reduced as more heat is dissipated. The main purpose of the heat sink is to keep the device temperatures within the limits stated by the manufacturers.

Factors to Consider When Choosing a Heat Sink

When choosing a heat sink, you should ensure that the thermal handling capacity of the heat sink matches with the processor. Consequently, you need to know the operating temperature limits of the device and the maximum dissipation power of the processor. You should also know the maximum limit temperature coming to the heat sink. Otherwise, these details are contained in the device owner’s manual. A mathematical formula can then be used to determine the heat sink suitable for the processor. 
Determining a Compatible Heat Sink
A suitable heat sink can be identified by calculating the rate at which the heat sink transfers heat from the processor also known as the thermal resistance. Thus, thermal resistance can be worked out by subtracting the maximum inlet temperature from the maximum case temperature. The difference should be divided by the maximum number of processor’s power dissipation.

Types of Heat Sinks

Manufacturing methods and final shapes are used in classifying the heat sinks. Some of the types of air-cooled heat sinks available from many vendors include the following: stampings, extrusion, bonded or fabricated, castings and folded.

On one hand, stamping sinks are made by fixing copper and aluminium sheet metal into desired shapes. These are mainly used for traditional cooling of electronic components. This is because they are cheap and can work for low density thermal issues. 

On the other hand, extrusion enhances the formation of two-dimension shapes that can allow dissipation of large amount of heat. Bounded or fabricated works by having a large surface area being exposed to the air steam. Castings are used for high density heat sinks that are required to give a high performance when cooling.

Conclusion

Different types of heat sinks are available from electronic device distributors. However, when selecting a heat sink you need to classify the air flow as either high flow forced convection or natural low flow mixed. Natural convection result when there is the air flow is not induced externally. The transfer of heat relies only on the natural flow of air around the heat sink. In this light, forced convection results when the flow of air is induced mechanical means.
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