基于四线测量法的智能微电阻测试仪设计

摘要

针对低电阻精确测量的应用需求，设计了一种基于四线测量法的智能高精度微电阻测试仪。系统采用模块化设计方式，包括供电电源、恒流源、A／D转换、显示与按键等单元。测试仪采用四线测量法，将电流流入回路和电压测量回路分开接线，并通过在电压提取端设计电压跟随器，使电压测量引线上的电流为零，可避免引线电阻和接触电阻对微小电阻测量的影响，大大提高系统的测量精度。实验测试结果表明：该仪器可以实现1μΩ～2MΩ范围内电阻值的高精度自动测量，同时还具有电阻分选功能，可与自动化生产线相连，完成电阻参数的分选工作。%According to the situation of need of accurate micro-ohm measurement, a micro-ohmmeter system based on four-line method is designed.This system adopts modularization design which includes power supply, constant-current source, A/D converter and display with LCD.The accuracy of measurement is apparently improved because the adop-tion of four-line method, which effectively canceled the affect of lead resistance and contact resistance in low resist-ance measurements by separating the current input and the voltage-sensing leads.The high accuracy also results from the design of voltage follower in the voltage-measuring port, making the current in voltage-sensing leads to be zero. The experimental data indicates that the device can realize the resistance measurement within 1μΩto 2MΩautomati-cally.Moreover, the tester has the function of resistance separation, which can be connected to automated production lines for the resistance parameter inspection.