Figure 7.

Analogue time-domain circuits. (a) A catalytic cascade that exhibits initially quadratic growth, with α ≈ 125 h⁻². Temporal trajectories are shown for a series of exponentially decreasing initial input concentrations. (b) A positive feedback circuit that exhibits initially exponential growth, with β ≈ 17 h⁻¹. The same series of exponentially decreasing input concentrations now yields a series of trajectories with linearly increasing half-completion times. (c) A pulse-generating circuit. Pulse amplitude depends on the input concentration. Here, we use a linear series of input concentrations between 0x and 1x. All simulations use 1x = 50 nM.