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由于半导体热敏电阻体积小、灵敏度高、热惯性小、成本低廉,因而在测温和控温工程中得到了极其广泛的应用。但因它的电阻-温度特性存在严重的非线性,必须研究有力的对策才能得到很高的精确度。以往的温度-频率变换器,大多把热敏电阻直接放在主振器频率网络中。本文介绍的方法是把热敏电阻间接地放在振荡器的正反馈支路中,和一个最佳补偿电阻串联,然后通过把振荡器的输出变换成恒流源向热敏电阻提供电流来改变反馈比,从而改变输出频率。另外,热敏电阻的功耗是随温度的增加而减小的。实验结果表明,采用本方法后,在0～100℃内,输出/输入关系是一条比较理想的直线,灵敏度35Hz/K。功耗在0℃时为600μw,在100℃时为46μW。如果增加1～2个补偿点,可望在更宽的工作温度范围内提高线
As the semiconductor thermistor small size, high sensitivity, thermal inertia, low cost, and therefore in the temperature and temperature control project has been extremely extensive application. However, due to the serious nonlinearity of its resistance-temperature characteristics, it is necessary to study effective countermeasures to obtain high accuracy. In the past, temperature-frequency converters, most of the thermistor placed directly on the main oscillator frequency network. The method described in this article is to place the thermistor indirectly in the positive feedback leg of the oscillator in series with an optimal compensation resistor and then change it by converting the oscillator’s output to a constant current source to provide current to the thermistor Feedback ratio, thereby changing the output frequency. In addition, the power dissipation of the thermistor decreases with increasing temperature. The experimental results show that, with this method, the output / input relationship is an ideal straight line with the sensitivity of 35Hz / K at 0 ~ 100 ℃. The power dissipation is 600μW at 0 ° C and 46μW at 100 ° C. If you add 1 or 2 compensation points, you can expect to increase the line over a wider operating temperature range