Well, in any case the reason why I wanted to tell you this is to tell you a little story which has much to do whith water, but in a rather different way.
In this case a colleague and I designed an electronic device taking example from a fountain in a ZEN garden ! We had the necessity to build a very small radio transmitter, working at 12 V, but as everybody that talks a lot whit his mobile phone knows, transmitting draws a lot of power, shortening considerably the life of the batteries. Furthermore in my case the only battery available on the market was the tiny 12 V battery, the 23A type for the one who are well informed.
Thus we decided not to transmit continuosly, but in very short bursts every (comparatively) long time, I cannot remember the exact value of the ON time but I think that the lenght of the transmission was of the order of microseconds, while the off time was 0.2 seconds (or, which is the same, the frequency of the cycle was roughly 5 Hz), so the transmission would actually occur for a very small time and the battery could last for a while rather than disappearing in a flash...
To achieve this pulsed behaviour we tried out many possible configurations, but there was a main problem:just the current needed to drive the "clock" part itself, let alone the radio section, was more than what the battery could give for a decent time.
The transmitter was actually meant to be fitted on a cat's collar and was paired by a directional ranger/finder to detect the transmitter (hence the cat), so I wanted this circuit to last one full week-end as a bare minimum, any longer would be greatly welcome.
I had in my mind an image of one of those bamboo fountains where water flows into an half pipe until it counterbalances the weight of the other side and discharges pouring the water into the nearby stream or lake.
We were trying to achieve that but always used far too cumbersome designs and techniques, but eventually we stumbled across one component, the awfully named UniJunction Transistor, or UJT for friends, actually we used a slightly weirder animal, a Programmable Unijunction Transistor, or PUT.
This little fellow turned out to be exactly what we needed to realize electronic version of the bamboo fountain, it is conceptually equivalent to a switch, which switching point one can control through a voltage level.
Off we went ! We calculated how much energy was needed to transmit the pulse, then we chose a capacitor big enough to store that amount at a voltage that we decided (hence the P in the name of the PUT, is that you decide at what tension the switch must close, in the UJT this is a fixed parameter) that was the one needed to power the radio section.
We also chose a resistor big enough to allow only a trickle of current charging the capacitor, so that it would be a long time before it gets filled and ready to discharge powering the radio module whith the energy stored within the capacitor, remember that 5 Hz is a very low frequency in electronics, it is rather unusual to find applications working at such a low frequency !
So the circut only needed to be programmed in the sense of what would be the switching voltage, thing this accomplished whith only two other resistor, that was it, the circuit was using so little power that even the tiny 23A battery lasted for around one month, and this even if we added a micro led to blink when the transmission was on, just to give a feedback about functionality and whith no other functions, in fact this led was using more power than the transmitting circuit itself, 10 micro Amperes against 7,5 Micro Amperes !!
I still love that simple yet very efficient design.