An instrument system for low-frequency (10−3–103 Hz) impedance measurements

An instrument system is presented for impedance measurements in the frequency range 10
⁻³
–10
³
Hz. The instrument features a three-frequency sinusoidal source with digital data acquisition. The former shortens the experimental duration whereas the latter facilitates simple computer analysis for the impedance. The system performs well even for cases with superimposed dc drifts. The results of some illustrative experiments are also presented.