This column deals with the thermal conductivity and melting points of liquid metals. Thinking about liquid metals, many people associate them with high temperatures. It is not widely known that some metallic alloys are liquid below 0�C, with the exception of course of mercury which was already known in ancient times. China's first emperor is said to have been buried in rivers … [Read more...]
On The Hate/Love Relationship Between The U.S. And SI
Last year I devoted some words on correligion: the religious belief in the usefulness of correlations to solve real-life problems. I forgot to mention that correlations have one big advantage; they are dimensionless meaning that they are the same for everyone, including people from outside the US. Unfortunately this is not the case for most common units, and the struggle for … [Read more...]
On The Challenges of Thermal Characterization of High-Power, High-Brightness LED Packages
Introduction In recent years, high-power, high-brightness Light Emitting Diodes (LEDs) have penetrated into an ever-increasing number of lighting applications. For such devices, maintaining a low die temperature is becoming a huge challenge because of the escalating power density (e.g., 200-300 W/cm2 for the latest generation). Active cooling solutions are rarely considered as … [Read more...]
Thermal Modeling Approaches Of GaAs Semiconductors
Introduction Predicting gallium arsenide (GaAs) semiconductor temperature is imperative since it affects the performance and reliability of the chip and the design as a whole. In many circumstances, the thermal engineer will be asked to provide expeditious and accurate answers to trade studies regarding various FET layouts and geometry, metallization schemes, and conduction … [Read more...]
Modeling Air-Cooled Heat Sinks As Heat Exchangers
Introduction The thermal resistance of a heat sink is a convenient way of describing its performance but, unlike its electrical counterpart, the thermal resistance of a heat sink is not a constant: it changes significantly with air flow. How we "understand" heat sinks is revealed by the models we use to describe their thermal resistance. Most thermal engineers use a single-term … [Read more...]
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