Proc. Int. Conference “Microtechnology and Thermal Problems in Electronics” MICROTHERM 2013, Łódź (Poland), June 2013, p.308-313 1 Static and Transient Thermal Properties of Resistors Embedded in Printed Circuit Boards A. Kłossowicz 1) , P. Winiarski 1) , B. Płatek 1) , W. Stęplewski 2) , J. Borecki 2) , A. Dzie dzic 1) 1) Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Wybrzeże Wyspiańskiego 27, 50- 370 Wrocław, Poland 2) Tele and Radio Research Institute, Ratuszowa 11, 03-450 Warsaw, Poland e-mails: adam.klossowicz@pwr.wroc.pl and andrzej.dziedzic@pwr.wroc.pl Acknowledge ments This work was supported by National Science Center (Poland) Grant DEC- 2011/01/D/ST8/07155 (Integration of passive elements with multilayer printed circuit board) and statutory activity of Wrocław University of Technology. Keywords heat transfer, thin-film resistor, thermal time constant, thermal transient measurement Abstract This work presents experimental results of static and transient thermal characterisation of thin-film resistors embedded in printed circuit boards and commercial discrete resistors. Objects of study were differ in sheet resistance, size or topology. Temperature on the test sample surface was determined based on thermographic measurement. Based on experimental results maximal surface temperature was found. Moreover thermal time constant was evaluated which can be helpful to determine how quickly temperature is getting at equilibrium state. Conclusions of this work can be helpful to define thermal behaviour and maximum power dissipation of the resistors embedded in printed circuit boards. Introduction Overheating is one of the most common reasons of electronic components’ damage. Not only the reliability and life time of the components, but also material properties, mechanical and dielectric strength are temperature dependent. Thermography, which is an easy method of studying the heat emitted by electronic circuits during their work, can be used for temperature measurement. This method can be very useful to define whether temperature on the surface of component does not exceed temperature of safe work. Many electronic devices work in the condition of cycle power dissipating, therefore their temperature can change many times over cycle period. With the aid of thermography heating or cooling curve can be plotted. Then to predict temperature changes a simple mathematical models can be used. The model can be useful to simulate the transient thermal behavior of devices and provide an aid to interpreting thermal changes.