Keeping LEDs Cool Gets More Manageable Through Simulation LEDs require careful temperature regulation which is accomplished by a heat sink; use simulation to control costs, size and shape of the heat sink Using a 3D model, electrothermal analyses predict self-heating, current crowding and forward voltage – performance indicators of LEDs IEEE Spectrum Insert 2013: Aulis Tuominen & Mika Maaspuro, Univ. of Turku, Finland; Toni Lopez, Philips, Netherlands; Sami Yllikäinen, Hella Lighting Finland Oy, Finland; Raimo Laitinen, Helvar Oy Ab, Finland The 3D geometry of the LED lighting device is composed of an internal LED module, a heat sink and a cap. Simulation results of air domain inside the cap shows temperature variations.