Analysis of Technical Characteristics of Temperature Sensors for the Design of Medical Thermometers

Abstract

The paper analyzes the technical features that must be taken into account during the construction of medical thermometers. An analysis of thermometers was carried out from the point of view of their suitability for monitoring temperature fluctuations on the surface of a biological object. The dependence of the resolution of the thermometer for different temperature ranges is considered. Expanding the range of measured temperatures leads to a decrease in the transmission coefficient, and vice versa, a decrease in the range leads to an increase in the steepness by the same number of times. A comparative analysis of various types of temperature sensors was carried out, in particular, a temperature-voltage converter (TC1047) from Microchip in a SOT23 case, a thermosensor (SMT16030) from Smartec in a TO18 case, a thermistor (203JG1F) from NTC in a DO35 case, (LM19) from National Semiconductor in a TO92 case, and (TSIC306) by Hygrosens in the SO8 case. The informativeness coefficients of the conversion of thermal sensors, and the dependence of the thermal time constant on the mass of the sensor in different types of housing are considered. It has been established that thermometers with sensors based on semiconductor diodes have a high perspective since sensors of this type provide high speed, short response time, operation in the mode of microcurrents, which maximally reduce self-heating of the sensor, high sensitivity, good linearity in a given temperature range (25...40°C), stability of electrical parameters. Along with high operational characteristics, sensors based on a semiconductor diode have a low cost.