A Cost-Effective And Accurate Electrical Impedance Measurement Circuit Design For Sensors

A circuit design with bespoke control software is described which has delivered precision in electrical impedance measurements of ~ 10ppm, after calibration. It is low-cost and applicable to jobs such as direct measurement using a sensor whose resistance changes with some physical quantity of interest; calibration at end of line in the production of such sensors; or calibration of equipment which may be out of warranty. It was developed using resistance temperature detectors (RTDs)