Rosenstark’s brilliant idea was to perform a pair of loop measurements with the return side terminated first on an open circuit and then on a short circuit , and then to suitably combine the two ...

They look for all the world like short circuits or open circuits, and yet work their magic and act to match feedline impedances or even as bandpass filters.

Further details of the setup and the results are provided in the study “ Outdoor implied open-circuit voltage imaging of perovskite solar cells using sunlight excitation,” published in Joule.