# Capacitor and hydraulic analogy

Would anyone kindly explain me the hydraulic analogy for the working of a capacitor w.r.t the article of wikipedia http://en.wikipedia.org/wiki/Capacitor... Help!!

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The analogy of a system of water pipes to represent an electrical circuit is well established and actually very useful, especially at elementary schools. Pressure = voltage and rate of water flow = current. Switches can be modelled as valves and resistors as restrictions in the pipe.

Anyhow, the hydraulic analogy of a capacitor can be though of as a rubber membrane that exerts a pressure proportional to the amount it's been stretched i.e. how much water you've pumped into it:

$$\text{Pressure} = \frac{\text{vol of water}}{K}$$

for some constant $K$. This has an obvious similarity to the equation for the voltage on a capacitor:

$$V = \frac{Q}{C}$$

where the charge $Q$ is represented by the volume of water and the constant $K$ represents the capacitance.

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