Autors: Mocci, A. M., Petkova, N. S.
Title: Analysis and Simulation of a Temperature Sensor: Using an NTC Thermistor, Voltage Divider, Low-Pass Filtering, and Output Linearization
Keywords: linearization, low-pass filter, LTSpice, NTC thermistor, Temperature sensor, voltage divider

Abstract: This article presents a simulation and analysis in LTSpice of a thermal sensor circuit featuring an NTC thermistor, designed for industrial and automotive temperature measurement. The proposed circuit incorporates a resistive voltage divider and a first-order low-frequency RC filter. The inherent nonlinearity of the NTC characteristic is examined through two hardware compensation strategies: selecting the series resistor by the classical geometric-mean rule, and adding a resistor in parallel with the thermistor sized by the three-point method. The simulation results, obtained via a parametric DC step in LTSpice, show that the series-resistor approach alone does not reduce nonlinearity over the intended 0°C-85°C range, while the parallel three-point method achieves a verified reduction of peak nonlinearity error by roughly a factor of two over the same range. The thermistor is modeled using the Beta equation with B = 3977 K and resistance at T = 25[°C], over an operating range from -40[°C] to 125[°C]. A comparison is also made with another calculation approach using the Steinhart-Hart equation. The Steinhart-Hart equation is a model that relates the change in the electrical resistance of a semiconductor to the change in its temperature. The model's own deviation from the manufacturer's tabulated resistance is also quantified, ranging from under 0.1% near the reference pair to about 24% at -40°C, and neither method fully linearizes the response across the entire -40°C to 125°C range.

References

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Issue

International Conference Automatics, Robotics and Artificial Intelligence, ICARAI 2026 - Proceedings, 2026, Albania, https://doi.org/10.1109/ICARAI70085.2026.11635510

Вид: публикация в международен форум, публикация в реферирано издание, индексирана в Scopus