Analysing the pressure effect on the contact resistance of electrical connections

Abstract

We propose an experiment intended for undergraduate laboratories, with the aim to introduce different novelties as a subject for a practical session or students project. We deal with the different components of the resistance in an electrical connection, with special focus on the contact resistance and its dependence with the applied mechanical load or pressure at the interface, since for a fixed geometry and connection materials, the contact pressure has a leading role on the final value of the resistance. The topics analysed are suitable for students with intermediate knowledge of physics. The dependence of the electrical resistance of two metallic rough surfaces with the applied pressure is studied and measured in the laboratory, and the weight of their different components is determined from calculations, simulations and measurements. The pressure dependence of aluminium and copper contacts have been analysed, since they are the most commonly used materials in electrical connections.