Improvement of the Metrological Characteristics of Biomedical Temperature Sensors Based on Transistor Structures

The analysis of metrological characteristics of biomedical temperature sensors based on transistor structures is carried out. It showed that the nonlinearity of the transfer function of the transistor-based primary transducer has the greatest influence on the measurement accuracy. We have proposed a linearization method based on the use of a multiplication device which forms compensatory voltage proportional to the quadratic component of the transfer function of the transistor-based primary transducer. This allowed to reduce the temperature measurement error up to ± 0.5·10
⁻³
°C over the temperature ranges 0… 80°C and up to ± 1·10
⁻³
°C over the temperature range 0… 100°C. In order to increase the accuracy of temperature measurement, an additional circuit for compensating the nonlinearity of the transfer function of a transistor-based primary transducer has been developed. It forms a quadratic voltage component proportional to the difference between the measured temperature and the temperature at the starting point of the second linearization range. The temperature measurement error does not exceed ± 0.39·10
⁻³
°C over the temperature range 0…100 °C.