A fluidic device controls fluid flow in channel from a source to a drain. In some embodiments, the fluidic devices comprises a gate, a channel, and an obstruction. The gate comprises at least one chamber whose volume increases with fluid pressure. A high pressure state of the gate corresponds to a first chamber size and a low pressure state of the gate corresponds to a second chamber size that is smaller than the first chamber size. The obstruction controls a rate of fluid flow within the channel based on the fluid pressure in the gate. The obstruction induces at most a first flow rate of fluid in the channel in accordance with the low pressure state of the gate, and at least a second flow rate of the fluid in the channel in accordance with the high pressure state of the gate.