Introduction One of the more complex thermal problems in electronics is the modeling of complete systems, such as an enclosure containing electronic components. A typical example would be a power supply, including heat sinks and a cooling fan. This problem becomes more difficult when there are multiple heat sinks and other large components arranged in an arbitrary manner inside … [Read more...]
Conduction heat transfer in a printed circuit board
In this issue, we examine heat flow in a printed circuit board (PCB), which typically is a layered composite consisting of copper foil and a glass-reinforced polymer (FR-4). A cross-sectional view of such a laminated structure is illustrated in Figure 1. The Figure indicates the numbering system that will be used for indicating the different layers, numbered 1 through to … [Read more...]
Thermal management of outdoor enclosures using phase change materials
Telephone equipment has traditionally been housed in large buildings, sheds and outdoor cabinets. The cooling of these facilities has been carried out using traditional methods. However, in many of the new systems being developed and deployed such as broadband ISDN, cellular and/or cable, heat dissipation densities will increase substantially [1]. Furthermore, the introduction … [Read more...]
The coefficient of thermal expansion
This is the second technical data feature that deals with the coefficient of thermal expansion (CTE). The first technical data feature, incorporated in the September 1997 issue, covered semiconductor materials, leadframes and solder alloys. This issue will discuss the temperature dependence of the CTE and present data on other materials that are of importance to electronic … [Read more...]
Measuring fluid velocity in electronic enclosures
Thermal analysis and characterization of electronic systems requires a knowledge of fluid velocity. In pursuit of this information, we often resort to measurement or calculation. The issue of measurement becomes a challenge since we are dealing with rather complex flows that tend to be highly nonisothermal. Therefore, it is our intention in this article to highlight the need … [Read more...]
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