Welcome to PEDRA

PEDRA is used to fit Electrochemical Impedance Spectroscopy Data using an Expandable Electrical Equivalent Circuit Model. PEDRA is different from traditional approaches; it determines how many responses can be supported by the data rather than fitting data to a proposed Electrical Circuit Model. PEDRA 9.0 supports multiple data files, user iterative fitting and overlay plots of results.

Services

Download Files

You must acquire WaveMetrics IGOR PRO to run PEDRA - Free 30-trial.

Try before you buy.

Send us an example data file for a free evaluation of the PEDRA Approach.

Case Studies and Help Files

The PEDRA approach has broad applicability in fitting EIS data.

Frequently Asked Questions

How is PEDRA different?

PEDRA uses a different approach to fitting EIS data.

1) Instead of providing a electrical circuit model (ECM), PEDRA uses an Expandable Randles (cascading resistance) or Debye (parallel resistance) ECM.

2) The number of responses in the model is dependent on what the data can support.

3) Initial parameters are obtained directly from a plot of the data.

4) The type of response is identified by the parameters that describe it; either circuit (Resistance, Capacitance, power law term) or Physical (Resistance, dielectric thickness, fractal or factional distribution).

5) Displaying results using a 3-parameter Gaussian equation allows results to be presented as an overlay graph directly within PEDRA.

How are files imported into PEDRA?

PEDRA supports three methods of importing data: 1) legacy files, e.g. PARC, Solartron, Gamry, 2) delimiated files having using an interface to delete header information and choose data columns of frequency, real and imaginary impedance, 3) copy and paste spreadsheet from a spreadsheet.

What is the procedure for performing a fit to the data?

1) Import multiple data files into the experiment.

2) Estimate how many responses maybe in the spectra (this can be changed during the fit)

3) Set the parameter constraints (optional) using the Preferences menu. This helps in fit convergence.

4) Perform autofit. The process will return the last successful fit iteration.

5) Continue with user iterative fit process until convergence is achieved (i.e. hold and release parameters observing fit, fit residuals and parameter error).

6) Continue fitting data files. Any previously fitted data on the list can be overlayed on current file for comparison.

7) Once data files are fit, display results on an overlay plot with either the frequency (time constant) or resistance as the x-axis.

8) Use the extensive capability of IGOR PRO to create publication quality graphs.

9) Export fit results in spreadsheet form that includes experiment information, fit results and columar data/fit columns.

How is PEDRA's program interface different?

First, everything is on one screen using three panels.

1) The Main Graph panel contains a ribbon menu and a graph of fit results with options to choose axis, a) Ratio (Zimag/Zreal), SpecView (Gaussian line graph), b) Bode plot, either Zreal, Zimag or Zmag, Phase Angle.

2) The Information Panel contains all fitting controls and fit results (parameters, parameter error, response influence and time constant).

3) The Fit Control Panel contains all imported files each with fit and overlay check boxes.

PEDRA does not replace traditional model-choice impedance software, but operates in concert with other software. Fundamentally PEDRA identifies the number and types of responses present in a data. This information is often sufficient to correlate physical characteristics to in-service behavior. However, the information can also be used to assist in choosing  an appropriate electrical circuit model used in traditional EIS software.

Contact us

Reach out to us to start your journey to better health.

About us

Parallel Electrical Debye Response Analysis is dedicated to improving the well-being of our clients through advanced electrotherapy and personalized wellness consulting. Located in Kingston, Ontario, we offer a range of services designed to address both physical and mental health. Our team of professionals is committed to providing safe, effective, and personalized treatments that cater to the unique needs of each client. We believe in a holistic approach to health, ensuring that our clients receive comprehensive care that promotes long-term well-being.