Allow simulation of the initial circuit model without having to fit it to experimental data

[banjaxedben]

I have just found this project and thought it might be very useful in a slightly different field: I test piezo-electric transducers and find the equivalent circuit by fitting to various models like "Butterworth-VanDyke": p(C0,R1-C1-L1).

Please correct me if I'm wrong, but as far as I can see, it is NOT possible to plot the Bode or Nyquist representation of a circuit that has not yet been fitted to some data?

Circuit string: p(C0,R1-C1-L1)
Fit: False

Initial guesses:
     C0 = 1.30e-09 [F]
     R1 = 6.35e+01 [Ohm]
     C1 = 1.86e-10 [F]
     L1 = 9.00e-02 [H]

Traceback (most recent call last):
  File "C:\Users\BenKinsella\GitLab\impedance\test.py", line 21, in <module>
    plot_nyquist(ax, circuit)
  File "C:\Users\BenKinsella\GitLab\impedance\env3.9\lib\site-packages\impedance\visualization.py", line 33, in plot_nyquist
    ax.plot(np.real(Z), -np.imag(Z), fmt, **kwargs)
  File "C:\Users\BenKinsella\GitLab\impedance\env3.9\lib\site-packages\matplotlib\axes\_axes.py", line 1634, in plot
    self.add_line(line)
  File "C:\Users\BenKinsella\GitLab\impedance\env3.9\lib\site-packages\matplotlib\axes\_base.py", line 2283, in add_line
    self._update_line_limits(line)
  File "C:\Users\BenKinsella\GitLab\impedance\env3.9\lib\site-packages\matplotlib\axes\_base.py", line 2306, in _update_line_limits
    path = line.get_path()
  File "C:\Users\BenKinsella\GitLab\impedance\env3.9\lib\site-packages\matplotlib\lines.py", line 999, in get_path
    self.recache()
  File "C:\Users\BenKinsella\GitLab\impedance\env3.9\lib\site-packages\matplotlib\lines.py", line 652, in recache
    x = _to_unmasked_float_array(xconv).ravel()
  File "C:\Users\BenKinsella\GitLab\impedance\env3.9\lib\site-packages\matplotlib\cbook\__init__.py", line 1298, in _to_unmasked_float_array
    return np.asarray(x, float)
TypeError: float() argument must be a string or a number, not 'CustomCircuit'

At the moment I have to use SPICE to simulate the circuit model (AC sweep). I feel like this should be possible in impedance.py?

[banjaxedben]

Sorry, my mistake. I somehow missed circuit.predict() in my code. It works fine, with a helpful warning

warnings.warn("Simulating circuit based on initial parameters")