A switching converter, drawn as a hydraulic circuit and solved as one — so you can watch where the energy goes instead of taking the equations on faith.
Because almost every version of it you have seen is a drawing.
The pictures in textbooks are static: a pipe, a narrow section, an arrow. They get you as far as Ohm's law and then stop, which is precisely where power electronics begins. Nothing in a static diagram tells you why an inductor fights a change in current, or where the energy sits during the moment a switch opens.
This runs the analogy as physics rather than illustration. The water has inertia, the piston has a spring, and the energy moving between them is solved in SI units and then drawn. When the switch opens, the inductor's momentum is what forces the diode to conduct — and you can see it happen, slowed down as far as you like, with the schematic and the waveforms tracking the same instant.
Flow and pressure come from a switched state model integrated in SI units. The picture follows the physics; the physics never follows the picture.
Water, schematic and waveforms share a single timeline. Scrub to any point in the switching cycle and all three show that instant.
Textbook CCM alongside the simulated result, with ripple and min/mean/max computed from the waveform rather than asserted.
The analogy breaks in specific, nameable places. Those are documented on the page rather than quietly hoped past.
Hydraulic resistance is genuinely nonlinear — real pipe flow shifts between laminar and turbulent — while an electrical resistor stays linear. Here the water carries the energy; in a real circuit most of it travels in the fields outside the conductor. And the analogy has nothing honest to say about semiconductor behaviour, which is why the switch is drawn as a valve and left there.
It is a lens for building intuition about energy storage and transfer. It is not a model of how electricity works. The schematic and the numbers are the authority — which is why they are never more than a glance away.
Early. The buck converter above is the first circuit released publicly; boost, buck–boost, flyback, forward, half bridge and full bridge exist and are being made trustworthy one at a time. The model currently solves a steady periodic state — start-up and load-step transients are the next substantial piece of work.
If you teach this material, or you remember ETH Zurich's iPES and have missed it since it went offline, I would genuinely like to hear from you.