一种多电极阵列腐蚀微电流检测方法

A multi-electrode array corrosion micro-current detection method

针对多电极阵列腐蚀电流十分微小很难准确测量的问题,文中结合STM32单片机技术,设计了一种基于多路电子开关切换实时比对测量的方法,获取较高精度的测量。在选用偏置电流极小的运算放大器的基础上,通过DAC自动调压、开关悬空与接地的切换方式,消除运放失调电压的影响;运用开关分别接地与腐蚀电极的切换方式,消除低频电流噪声的干扰,提高各阵列微电流的测量精度。实验表明:该方法能够完成腐蚀电极0.1μA级精度的测量。

It is very difficult to be measured accurately for the micro corrosion current of multi-electrode array.This paper designs a measurement method based on multi-channel electronic switching real-time comparison measurement to obtain high precision measurement using the STM32 single chip microcomputer technology.Choosing the operational amplifier with small bias current order of pA,the impact of offset voltage is eliminated by applying automatic voltage regulator of ADC,floating and connecting ground of switch.The switch were connected to ground and corrosion electrode in turn to eliminate the interference of low-frequency current noise and improve micro-current measurement accuracy of each array.The experimental results show that this method for corrosion electrode current can arrive at the accuracy of 0.1μA.