Miniature thick film position sensor for real time in situ monitoring at the contact point of automotive connectors

The fretting phenomenon in electrical contacts, which induces electrical distortions (or noise) and high contact resistance, is believed to be one of the main causes of failure for electrical systems used in the automotive industry. In order to carry out a comprehensive evaluation of fretting effects, a thick film position sensor for real time in situ measurement of relative movement at the contact point for connectors has been designed. The in-house fabricated sensor was produced by screen printing a strip of resistor on an alumina substrate. Based on the potential divider working principle, the measured voltage output from the sensor corresponded to the relative position of the contact point. A resolution of 5 sm was achieved. This paper focuses on the investigations of the accuracy and thermal stability of the thick film position sensor when subjected to a series of laboratory tests.