Design And Implementation Of Electrochemical Sensor Measuring Circuit

Electrochemical sensor responds to the change of organism or chemistry and output electrical signal by some discipline. Reflect the authenticity of the organism or chemistry's changing discipline depended on the accuracy of the measuring. It's very important that make high accuracy measuring instrument.In electrochemical sensor measuring, sometimes kinetic current is so weak like nA level, even much smaller in measuring contamination because of reaction mechanism, so it's important to design the weak current measuring circuit. Nowadays, the major technical matters in weak current measuring is signal conditioning circuit, noise processing circuit and how to reduce external disturbance.This paper research on weak current measuring of electrochemical sensor measuring, summary characters of every circuit based on analyzing the current development situation of weak current measuring method. Design a weak current measuring circuit depended on the special environment which can be used in portable or table type instrument.This paper designs the resolution of 10nA measuring circuit. This paper designs the circuit based on making emulation about I-V convert circuit and analyzing the practical setting. This paper designs the power supply circuit by analyzing the influence of ripple. This paper designs the noise processing circuit based on using targeted treatment on low-frequency measurement for a better effect in noise processing circuit. Last, this paper also designs the cyclic voltammetry based on LabVIEW for evaluating the electrochemistry sensor and realize by NI PXI-4130, the result can meet the requirements by comparing with electrochemical workstation.The cyclic voltammetry designed in this paper is easy to use and strong operability. Weak current measuring circuit is accurate in measuring, large range and automatic changing measuring range based on the current value.