We use electromagnets in all sorts of other applications, from motors to speakers and even medical scanners.

我们在各种其他应用中使用电磁体，从电机到扬声器，甚至医疗扫描仪。

One type of temporary magnet is called an electromagnet.

一种类型的临时磁铁称为电磁体。

And finally, electromagnets need a power source in order to generate the electricity required to produce magnetic fields.

最后，电磁体需要电源才能产生产生磁场所需的电力。

Let's take a moment to look at the definition of what an electromagnet is.

让我们花点时间看一下电磁体的定义。

This makes electromagnets quite different from permanent magnets.

这使得电磁体与永磁体有很大不同。

Electromagnets are typically made of loops of wire and a coil.

电磁体通常由线圈和线圈制成。

So let's take a look at that and compare permanent magnets to electromagnets.

让我们看一下并将永磁体与电磁体进行比。

A turbine spins a magnet inside a coil to produce electricity, and since electromagnets need a power source, this turbine is powered by wind.

涡轮机旋转线圈内的磁铁来发电，由于电磁体需要电源，因此该涡轮机由风提供动力。

To read that information, your computer rotates sections of the disk past the head, which is a small electromagnet that has a coil of wire.

要读取该信息，您的计算机将磁盘的某些部分旋转经过磁头，磁头是一个带有线圈的小型电磁体。

Permanent magnets do not need a power source, but this means that we can also turn electromagnets on and off, which is pretty cool when you think about it.

永磁体不需要电源，但这意味着我们也以打开和关闭电磁体，想想看，这真是太酷了。

You can't change the north and south poles on these magnets, but as we now know, for electromagnets, we can change these poles by changing the direction of the electrical current.

你无法改变这些磁铁上的北极和南极，但正如我们现在所知，对于电磁体，我们以通过改变电流的方向来改变这些磁极。

So, if we have an electromagnet with a north and south pole that looks like this and a current flowing in this direction, well, we can change the poles and the direction of the current.

因此，如果我们有一个具有如下所示的北极和南极的电磁体，并且电流朝这个方向流动，那么我们就以改变电流的磁极和方向。

The Casio brothers decided to build their Casio calculators off a device called a " solenoid." So, a solenoid is basically a metal sort of plunger inside an electromagnet, so just a coil of wire that runs round it.

卡西欧兄弟决定用一种称为“螺线管”的设备来制造他们的卡西欧计算器。因此，螺线管基本上是电磁体内部的一种金属柱塞，所以只是围绕它的一圈线圈。