USE OF RESISTORS MADE WITH THICK-LAYER TECHNOLOGY, THOSE NOT SENSITIVE TO LOW TEMPERATURES IN LOAD CELLS

A strain gauge made of thick-film resistors has a great potential for use in civil engineering owing to its relatively high voltage sensitivity, stability, low production cost, and long-term service capacities. However, a persistent drawback of strain gauges is their thermal sensitivity. To address this problem, it is advisable to propose and manufacture a strain gauge made of thick film resistors that do not sense low temperatures. This paper makes a close look into the effects of resistor paste components and baking temperature on the temperature coefficient of resistance (TCR) of a thick-film resistor. Thick film resistors made from RuO2 concentrations from 10 wt% to 30 wt% baked at different temperatures on an Al2O3 substrate, have been investigated. The relationship between resistor resistance, TCR and scale factor (GF) has been subject for studies. Findings show that TCR rises with an increase of the RuO2 concentration and baking temperature. Near the minimum (Tmin) of the resistance-temperature curve, the temperature has the least effect on the resistance value, and a thick-film resistor can be considered insensitive to temperature in a certain range. The ratio of TCR to GF and Tmin depends on the film resistance of thick film resistors. By varying the concentration of the conductive phase and the baking temperature, the film resistance of thick-film resistors can be controlled, and low-temperature strain gauges can be achieved for different ambient temperatures.

Перевод пока недоступен