A VERSATILE COMPUTER-CONTROLLED MEASURING SYSTEM FOR RECORDING VOLTAGE-CURRENT CHARACTERISTICS OF VARIOUS RESISTANCE SENSORS

A computer controlled measuring system for generating the static volta ge versus current (V-I) characteristics of various resistance sensors is described. Based on the measured data, the dissipation constant of sensors can be calculated The software enables experiments with severa l types of resistance sensors having current controlled V-I characteri stics to be performed. Experiments were carried out with negative temp erature coefficient (NTC) thermistors, metal wire and metal film anemo meter sensors, as well as with the positive temperature coefficient (P TC) silicon temperature sensors. The computer-controlled system makes possible the precise generation of the individual static V-I character istics of a sensor in relatively short duration experiments, without t he necessity of knowing the sensor time constant. The eventual damage to a sensor during the test, which frequently occurs in manually contr olled measurements, is prevented by appropriate software solutions. By studying the V-I characteristics of PTC silicon temperature sensors a t various air speeds it has been shown that these sensors are potentia lly very suitable for air speed measurements, in which high sensitivit y, robustness and relatively slow time response is desirable.