The low pass filtering water machine
Don't expect the quality of the water improved !!!
This is a visual approach showing how an electronic RC low pass filter works. It shows that frequency, phase are artificial concepts!
The levels of the (blue) water in the recipent A and B are respectively the input
and output of the system (The levels correspond to the voltages in electronics)
The recipient A is moving up and down thanks to the rotating engine.
The recipient B communicate with A through a small tube limiting the
flow.(The tube corresponds to the resistor, the recipient B to the capacitor).
Watch the ouput level range diminishing and the phase increasing when you increase speed !
Another differential equation is solved by the way : the shape of the tube.
The weight of each element of the tube is balanced by the tension on the left side and the right side. The total length of the tube should be of course kept constant.
This is the equation for a chain or telephone line between poles etc.
This non linear equation is solved in a double loop by Newton-Raphson method (for the shape) and secant method (to keep a constant length) for each position.
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