A memristor (short for memory resistor) is the newly discovered (fourth) fundamental circuit element, the first three being the resistor, capacitor, and inductor. It was realized in 2008, some 37 years after its existence was postulated in 1971. This Demonstration shows the I-V curves for a memristor, modelled as two regions of different resistivities in series, and their dependence on the period of the applied AC voltage and the initial fraction of the low-resistivity region. The unusual I-V curves, plotted for time , show hysteresis that increases with and leads large region of negative differential conductance .

Starting from the origin, the blue curve shows I-V for , the red for , and the subsequent blue shows the I-V for . The black dots mark I-V for temporally equidistant points in the interval .

Snapshot 1: typical hysteresis loop; iff implies that a memristor is a purely dissipative element

Snapshot 2: typical I-V at low frequencies (high ) shows large regions of negative differential conductance ; this behavior is also induced by increasing the initial fraction of the low-resistivity region

Snapshot 3: the hysteresis is suppressed at high frequencies because the fraction of the low-resistivity region does not change significantly over the period for small

Analytical results underlying this Demonstration, as well as references to the original experimental (2008) and theoretical (1971) papers, can be found at http://arxiv.org/abs/0807.3994.