This simulation compares the voltage waveforms across resistor–resistor (R-R), resistor–inductor (R-L), and resistor–capacitor (R-C) circuits when driven by a square-wave input. In the R-R case, the voltage simply follows the input because resistors do not store energy; the waveform is sharp and identical to the source. In the R-L circuit, the inductor opposes sudden changes in current, producing a smooth rising and falling voltage with spikes when the input switches. This creates the yellow exp