capacitor in a circuit
"Putting a capacitor into your circuit is like building an extra reservoir - a water tower, for example - to capture the flow. You can then let the flow out of your water tower (capacitor) at a very steady rate, or all at once, in a burst. This extra reservoir can be useful in a couple of different ways. For example, it might be important that the machine being powered by your current (whether a water wheel or light bulb) receives a very constant current that is not too big or too small. Again, too big might hurt the machine; too small and it will stop working."
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.