Simultaneous Measurement of Conductance and Differential Conductance with Operational Amplifier and Fourier Spectrum Analyzer
Wenbo Xiao, Xingdao He, Jiangtao Liu · 2011
We propose a method to measure conductance and differential conductance simultaneously using an operational amplifier and Fourier spectrum analyzer.Theoretical analysis is conducted to study the output voltage characteristics of a nonlinear diode under AC and DC bias.Assuming that high-frequency contents are much smaller than low-frequency components in that output voltage,a measurement equation for conductance and differential conductance of the diode is derived.And,an analytical expression of the physical relationship is presented.Simulation and experiments show validity of the method.We also find that the differential conductance signal is an order of magnitude stronger than the conductance signal when the diode is under the same DC bias.