Exercises - Advanced Impedance Analysis
2020-11-16
0. Software for this exercise
For this exercise we will use the LinKK tool that can be downloaded for free from https://www.ia
m.kit.edu/wet/english/Lin-KK.php
and Elchemea Analytical which is available to use online here: https://www.elchemea.com/ (-->
"Try Elchemea Analytical").
The files are available as comma separated (.csv), tab separated (.tsv), and as Excel sheets (.xlsx).
LinKK tool works well with .xlsx files. For Elchemea it is possible to copy/paste the contents of the
files into the field that is made available when pressing:
in order to load the data. Here .csv or .tsv files should work best.
1. Single -(RC)- circuit, with and without noise
a) Compare the residuals plots obtained in a Kramers-Kronig transform compliance test.
b) Try to carry out a CNLS fit using Elchemea on each data set (which is described by the same
parameters [R0=, R1=, C1=]) and see how well you recover the original circuit parameters with and
without noise
c) what can you do to decrease random noise in a practical experiment?
Files:
eis_R_RC.tsv
eis_R_RC_noisy.tsv
2. Randles circuit, with and without noise
a) Repeat steps 1a-b on the below data files.
b) What do you think the benefit of using weighting might be on a data set like this? How is it
different to the dataset in 1?
Files:
eis_Randles.tsv
eis_Randles_noisy.tsv
3. Data with Drift
The files for this exercise comes in three different versions, two with drift in the dataset and one
with data that has no time-dependence of the parameters, all based on the same -R-(RC)- circuit.
1) Plot the three data-sets and discuss what may give rise to the differences in the two data-sets
with drift - which circuit parameter is changing with time?
2) Compare the residuals plots obtained in a Kramers-Kronig transform compliance test using
KKtest for Windows or LinKK tool. How can you detect drift?
3) Discuss possible causes of drift in an impedance measurement.
Files:
eis_R_RC_no_drift.tsv
eis_R_RC_drift_1.tsv
eis_R_RC_drift_2.tsv