thats because you have more than one kind of dualism in circuits... you have parallel-series dualism, and you have capacitor-inductor dualism... there are other kinds too like magnetic-eletric dualism.
@trinsec indeed
@freemo Then you have analogs in other domains. I read the manual for WW2 torpedo, and it has a couple of pneumatic op-amps for the steering and depth control.
Also worked at Haskel where they made pneumatic DC-DC converters, with a large and small cylinder and a mechanical valve oscillator to make it go. You can get 10K PSI from shop air that way.
A player piano has a vacuum power supply with a regulator, and a vacuum transistor at each piano key.
@freemo Methinks you mistooted again. ;)