Implementation of a data acquisition system for contactless conductivity imaging

A data acquisition system is realized to image electrical conductivity of biological tissues via contactless measurements. This system uses magnetic excitation to induce currents inside the body and measures the magnetic fields of the induced currents. A magnetically coupled differential cod system is scanned on the conductive object by a computer controlled scanning system. A data acquisition system is constructed using a PC controlled lock-in amplifier. 1.64 V secondary voltage difference can be measured for 0.6 S/m solution. The average data acquisition time is 4.67 see/mm². 8 mm diameter objects with conductivity 0.2 S/m can be detected with this system.