HEAT SINK – TYPES
(BASED ON THE TYPE OF CONVECTION)
Heat sink are generally classified depending upon the types of convection used, as
- Passive heat sink
- Active heat sink
1.1.1 PASSIVE HEAT SINK (STANDARD HEAT SINK)
The first type of cooling applied to processor was the heat sink, a device user for a very long time in electronics to cool hard devices. Television and stereo have used them for years, and these are also found in power supply and even on motherboard. These are now sometimes called “Passive” heat sink as well, the term meaning simply that are no moving parts with this type of cooler, un like a mounted fan.
The operation of heat sink is quite simple; it cools the processor using thermal conduction and radiation. A large piece of metal (usually aluminium) with fins on it is attached to the surface of the processor. The metal of the heart sink draws the heart from the processor, and air blowing through the fins on the heat sink cool it.
The larger the heat sink and the more pronounced the fins on the heat sink the better the cooling. Some of the heat sink in newer PCs can be positively enormous, covering a surface area two three times that of the processor it self.
1.1.2 ACTIVE HEAT SINK (CPU FAN)
An active heat sink or CPU fan is enhancement to the standard or passive heat sink. It too uses finned piece of metal attached to the surface of the processor to conduct heat way from the CPU so it can be cooled by air.
However, active heat sink go one step further, adding a small fan that blows directly on to the heat sink metal to ensure direct air cooling. The remove the passive heat sink’s dependence on the power supply fan for cooling the processor.
Active heat sinks like passive once can come either to the processor with adhesive or using clips. When clips are used, heat sink compound should be placed between the processor and heat sink to ensure good thermal conductivity and hence proper cooling the processor.
The typical CPU fan costs about 5$, and is made using a cheap, short life span sleeve bearing motor. These fans are quite prone to failure, and when (not if ) they lock up, the processor will usually over heat very quickly because it is dependent of the fan for cooling.