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Element equations and parameter names

Parameter limits for the current circuit

Bounded methods keep every parameter between these limits. Untick “shared” to give a parameter one value per dataset in a global fit. Parameters that span decades (R, C, L, Q, Aw, B, τ) are varied in relative steps during a fit, which keeps them positive; n, α and β in absolute steps.

Start values for new elements

Used when an element is added to the circuit. Stored in this browser.

Settings file

    やっぱり

    Yappari JS

    Yet Another Program for Analysis and Research in Impedance. One equivalent circuit is fitted to one or to thousands of impedance spectra. Browser version of Yappari 5.1 (LabVIEW) by Nita Dragoe, Université Paris-Saclay, ICMMO.

    Working with it

    1. File, read data, or drop files on the window. New datasets appear at the top of the list.
    2. Build the circuit in the Model tab by clicking elements, or type a circuit code.
    3. Select a dataset, set start values (mouse wheel over a parameter), tick the parameters to fit, then Fit selected in the Fit panel (or F9). Switch the mode to Global for one fit with shared parameters.
    4. For many spectra: in Parameters, copy the values to all datasets; select all with Ctrl+A in the list; Fit selected.
    5. Save parameters, data, a report or the whole project from the File menu.

    Circuit code

    Elements written next to each other are in series. Round brackets put their content in parallel, square brackets put their content in series inside a parallel group. R(RQ)(Q[RW]) is Rs + (R‖Q) + (Q‖(R + W)). Elements: R, C, L, Q (constant phase element), W, Wo, Ws (Warburg), G (Gerischer), HN (Havriliak–Negami). Numbers name the elements (R1, Q2) and are added for you.

    Checks and relaxation times

    The DRT tab shows the distribution of relaxation times of the selected datasets (Tikhonov with non-negativity, Fisk or Gold; R∞ and Rpol from the data), with peak estimates of R and C. Analysis, Z-HIT checks a spectrum: |Z| rebuilt from the phase should match the measured |Z|. Contributions colours each part of the series chain, on the plots and in the circuit drawing.

    Mouse and keys

    Plotsdrag to zoom, shift-drag or right-drag to pan, wheel to zoom, double-click to autoscale
    Parametermouse wheel or arrow keys change the value; Shift for larger steps, Alt for smaller ones
    Dataset listCtrl+A all, Shift+click range, Ctrl+click one more, Delete, F2 or double-click to rename, drag to reorder
    AnywhereF9 fit selected, Ctrl+S save project
    Drawingclick to select, Delete to remove, Ctrl+Z to undo, Esc to deselect

    Citing

    N. Dragoe, Materials Lab 2024, 3, 230031, doi.org/10.54227/mlab.20230031. Documentation on the github repository, You can also use an older but faster version in LabVIEW: nitad54448.github.io/yappari-5-1.