关键词: 非平衡电桥, 热敏电阻, 符号计算

Abstract: Measuring the temperature characteristics of thermistors using an nonequilibrium bridge and achieving a linear voltagetemperature response is an important project in university physics laboratory teaching. The elaboration of the experimental principle involves complicated formula derivation, which is not convenient for teachers to explain and is not conducive to students understanding of the core idea. In this paper, combined with the symbolic calculation function of the SymPy library, the model derivation and parameter solving are simplified and automated, the linearization conditions of the negative temperature coefficient resistance and the positive temperature coefficient resistance are discussed in a unified manner, and then the linearization parameters under the polynomial model of the resistance characteristics of the negative temperature coefficient resistance are solved, and finally the NTC thermometer experiment combined with the SymPy library is designed to verify the advantage of small linear fitting error under the highorder resistance model. Through the digitalization of physics teaching and the comparison between models, the importance of physics ideas in teaching is highlighted, and students understanding of experimental principles is deepened.

Key words: nonequilibrium bridge, thermistor, symbolic computation