Interactive training resources for the Bluefruit team.
Everything on this site is currently about EIS. Start with the self-assessment to find your gaps, work through the tutorials, then retake the assessment to see what shifted.
Use it on its own, or bracket the tutorials with it: assess → learn → reassess. Diagnostic, not a test — your confidence matters as much as your accuracy.
Ordered by suggested progression — each tutorial builds on the previous. Each page has forward and back links so you can walk through in sequence.
The starting point. V = IR: voltage, current, resistance and the relationship between them. Play with the numbers and see what falls out.
Move around the complex plane, see the real and imaginary parts, get a feel for how numbers with an i in them actually behave.
Explore three views of complex impedance. Change equivalent-circuit component values and see the Nyquist, Bode and Cole–Cole plots respond in real time.
Linear time-invariant systems, why they matter for electrochemical impedance spectroscopy, and how the maths of the earlier steps ties into the way EIS actually measures things.
How to talk about uncertainty: error bars, confidence intervals, and what “reliable” actually means when you say a number.
Optional deep dives — not part of the main sequence and not covered by the assessment. Useful when you need more background on a specific piece.
What actually happens inside a resistor and a capacitor, and why capacitors make the measured current drift out of sync with the applied voltage — the phenomenon that makes EIS a spectroscopy in the first place.
Four nodes, every measurement. The AD5940 does the DFT and complex arithmetic; it cannot guess the wiring. Two- vs four-wire, driving your own router, and firmware that keeps it safe.
How the AD5940 turns a sampled current into one impedance point, and how eis-testbed picks the DFT size, window and frequency for each point. Six guided steps with live controls.
Same ground, different medium — useful if you prefer video, or want a second angle after working through the tutorials.