Popular topics · Modelling and fitting (ZFit, ZSim)

How is impedance data simulated with Z Sim?

Z Sim in EC-Lab and BT-Lab generates impedance data over a chosen frequency range from a selected equivalent circuit and its parameters; it allows hypotheses to be tested without measuring, in research and in teaching.

Key points

The equivalent circuit is selected or created with the text or graphic editor (ZFit tutorial video 3).
The frequency range and sampling are set: total points over the whole range or points per decade; linear or logarithmic spacing.
'Calculate' runs the simulation; the result can be switched to Nyquist, Bode, Black or admittance representations.
It is especially useful for studying low-frequency behaviour: a measurement from 1 MHz to 10 µHz with 6 frequencies per decade can exceed 100 hours, whereas the simulation is instantaneous and has no time-variance problem (see AN61).
It is also used to study the effect of high-frequency inductance on ohmic-drop determination.

Figures

**Figure 1.** Z Sim interface: equivalent circuit (R1 + C2/R2 + W3), parameters, frequency range and sampling.

**Figure 2.** The representation of simulated data can be switched between Nyquist, Bode, Black and admittance plots.

Images: Bio-Logic Science Instruments; taken from the source article.

Videos

Simulation with Z Sim (Bio-Logic video)Watch on YouTube

Related application notes

How is low-frequency impedance (diffusion) in batteries interpreted? Battery AN61
How is the ohmic (internal) resistance of a battery measured with EIS? Battery AN62
When is the modified inductance element La needed? Battery AN42
What is an equivalent circuit, and how is it built and fitted with Z Fit? Battery AN14

Related curriculum module: Electrochemical Impedance Spectroscopy (EIS)