为了满足电化学分析系统中宽量程范围内微电流的准确测量需求,设计了一种新型低功耗宽量程精密恒电位仪,提出了基于补偿式恒电位控制与两级比例电阻法相结合的微电流检测方法,实现10~(-10)~10~(-3)A量程范围内的准确电流测量。文中给出新型低功耗宽量程精密恒电位仪的硬件电路设计,利用等效模型电路推导了电路传输特性,并采用自制的三电极自制针状传感器和高精度电阻模拟生物电化学分析过程。仿真和实测结果表明,新型低功耗宽量程精密恒电位仪信号输出稳定,在10~(-10)~10~(-3)A量程范围内的微电流检测相对误差小于1%,据此设计的便携式恒电位仪已实际应用于组织工程液压生物反应器智能化监测系统。
In order to meet the requirement of accurate measurement of wide-range micro-current in the electrochemical analysis system,a novel wide-range precision potentiostat with low power dissipation is designed in this paper. New detection method based on compensated potential control and two-stage proportional resistance method is proposed to achieve accurate measurement of micro-current in the wide-range of 10~(-10)~ 10~(-3) A. The hardware circuit design of novel wide-range precision potentiostat with low power dissipation is proposed,the transmission characteristic of the circuit is deduced by equivalent model circuit,and the bioelectrochemical analysis process is simulated by using homemade three-electrode needle sensor and high precision resistors. The simulation and experimental results show that the signal output of the novel wide-range precision potentiostat with low power dissipation is stable,the relative error of micro-current detection in the wide-range of 10~(-10)~ 10~(-3) A is less than 1%,and the novel portable potentiostat according to the proposed method has practical application in tissue engineering hydraulic bioreactor intelligent monitoring system.