One contact operates like a capacitor plate, the other like a battery electrode.

其中一个电触点相当于一个电容板，另一个电触点相当于电池的电极。

And that potential energy is actually stored within the electric field between a capacitor's charged plates.

而那个势能其实是储存在里面的 电容器两极板之间的电场。

To measure potential energy in an electric field, let’s imagine a positive test charge that’s moving between a capacitor’s plates.

为了测量电场中的势能， 让我们想象一下在电容器极板之间移动的正测试电荷。

When we express it mathematically, voltage is equal to the negative electric field times the distance between the capacitor plates.

用数学表示，张力是 电场击中电容器的两个极板。

To measure potential energy in an electric field, let's imagine a positive test charge that's moving between a capacitor's plates.

为了测量电场的势能，让我们想象一下 正测试电荷在电容器的两个极板之间移动。

Because it’s largely why capacitors are so incredibly useful – from defibrillators to electronic components: When a capacitor’s plates store electric charge, they’re actually storing energy!

因为这在很大程度上是电容器如此有用的原因——从除颤器到电子元件：当电容器的极板储存电荷时，它们实际上是在储存能量！

This effect carries all the way through, until the last plate of the third capacitor has a negative charge equal and opposite to the first capacitor’s positive plate.

这种效应一直持续到第三个电容器的最后一个极板具有与第一个电容器的正极板相等且相反的负电荷。

This effect carries all the way through, until the last plate of the third capacitor has a negative charge equal and opposite to the first capacitor's positive plate.

这种效应一直持续，直到第三个电容器的最后一个极板具有与第一个电容器的正极板相等且相反的负电荷。

We often want to know how much energy is in a certain location, like between capacitor plates, so we use energy density, or the amount of energy stored in the electric field per unit volume.

我们经常想知道特定位置的能量，例如两个板块之间的能量， 所以我们使用能量密度，或者说在一体积内存储在场中的能量。