频率自适应电流源克服电容影响的电导率测量

Electrical conductivity measurement using frequency self-adaptation current source to surmount the influence of capacitance

在电导率的测量中,为减小极化作用的影响,交流电源的频率越高越好,但频率提高的同时电容作用的影响也随之增强,因此,选择合适的频率是提高测量精度的关键。本文提出了一种在电导率测量中如何选择合适的信号测量源工作频率的方法,在恒流源驱动下,判断电导池输出电压导数可自动确定信号测量源工作频率。本文从理论上对该方法进行了分析,并给出实现的硬件电路和实验结果。

In conductance measurement process, high signal frequency can decrease the error generated by polarization, but it can also increase the error caused by cable capacitance at the same time. So, it is a key point to choose a suitable frequency to improve the measurement accuracy. This paper introduces a method for choosing a suitable working frequency of the measurement signal source. Driven by a constant current source, the output voltage derivative of conductance pool can be estimated and the working frequency of the measurement signal source can be determined automatically. This paper not only analyses the method theoretically but also provides the practical circuit and experiment results.