江苏春晨电缆有限公司生产YFFB扁电缆YFFB行车扁电缆拖链扁电缆，
其实严格来讲，这个“插头”叫开关电源适配器，目的是将电网传来的交流电转换为直流电传输进电子设备中。笔记本电脑的电源适配器更大，冬天暖手更方便~
In fact, this "plug" is called the switch power adapter, the purpose is to convert the alternating current from the power grid to the direct current transmission into the electronic equipment. The power adapter of the laptop is bigger, and the warm hand is more convenient in winter.
那为啥要把交流电换成直流电呢?让我们从头讲起。
Why do you want to change the AC to DC? Let's talk about it from the beginning.
电是一种自然现象。电荷静止或移动会产生很多有意思物理现象，比如雷雨天气中会看到的闪电、冬天脱毛衣的时候噼里啪啦的火花。后来，科学家们从各种电效应中发现规律，于是发明出了电池、发电机、电动机。
Electricity is a natural phenomenon. The charge or mobile will have a lot of interesting physical phenomena, such as thunderstorms will see the lightning in the winter, when the crackling sparks off a sweater. Later, scientists discovered laws from various electrical effects and invented the batteries, generators, and motors.
先用直流电，还是先用交流电?YFFB扁电缆YFFB行车扁电缆拖链扁电缆
First use direct current, or the first use of alternating current?
220伏/50赫兹交流电是我国的供电标准，所以很多人都以为家用电器用的都是交流电。至于直流电，大概除了那句广告中会念叨的“直流变频空调”，想不到其他的了吧。
220 volt /50 Hertz alternating current is the power supply standard of our country, so many people think that the household appliances are all alternating current. As for the direct current, it may not be possible except for the "DC frequency conversion air conditioning" that will be said in the advertisement.
其实，直流电应用很广泛，你肯定见过，也用过。比如：
In fact, the use of direct current is very wide, you must have seen, also used. For example:
定义
Definition
直流电，是指方向不随时间发生变化的电流。YFFB扁电缆YFFB行车扁电缆拖链扁电缆
Direct current refers to the current that does not change with time.
交流电，是指大小和方向都发生周期性变化的电流。
Alternating current (AC) refers to a current that changes periodically in size and direction.
从示波器观测，一个是直的，一个弯的……
From the oscilloscope, one is straight, a curved one...
反正都是电，感觉差别不大?
It's all electricity anyway, and it doesn't feel very different?
No~No~No~
No~No~No~
让我们翻开历史，讲点八卦!
Let's turn over the history and tell the gossip!
直流电，是电力革命急先锋。在早期的电磁学实验中，人们总是想方设法把产生的电能转变为直流电。
Direct current is the pioneer of the electric power revolution. In the early electromagnetics experiment, people always tried to transform the generated electric energy into DC.
1879年，托马斯˙爱迪生制成第一只碳丝白炽灯，吸引了大量投资。此后，小爱同学一路顺风顺水，1882年的一个夜晚，110伏的直流电输送到纽约曼哈顿整个街区……大家终于可以扔掉煤油灯啦~
In 1879, Thomas Edison, made the first carbon filament incandescent lamp, attracted a lot of investment. Since then, Edward I wish you a happy voyage. smooth, one night in 1882, DC electricity to New York Manhattan the whole block of 110 volts...... You can finally throw away the kerosene lamp.
然而，直流输电的弊端也随着使用范围的扩大而逐渐显现：电压不变的情况下，供电距离的增加和用户的增长加剧了线路损耗。小型直流中心电站供电区域仅限于2公里不到的方圆内。
However, the drawbacks of HVDC are also increasing with the expansion of the scope of application. Under the condition of constant voltage, the increase of power supply and the growth of users aggravate the line loss. The power supply area of a small DC central power station is limited to the square of less than 2 kilometers.
因为损耗量=电流电阻，所以减小电流就能减少损耗。
Because of the loss of current = - resistance, so reducing the current can reduce the loss.
在传输功率保持不变的情况下，电流和电压成反比，所以，提高电压就能减小电流，减小损耗。
When the transmission power remains constant, the current is inversely proportional to the voltage, so increasing the voltage can reduce the current and reduce the loss.
当时高压直流技术尚不成熟，直流电变压比较复杂。这时候，塞尔维亚小青年尼古拉˙特斯拉背着书包，跨越大洋奔向偶像爱迪生。他有一个不太成熟的小建议——交流输电。交流电机比直流电机结构更简单，容易变压，可以简单、经济、可靠地解决提高输电电压的问题。
At that time, the high voltage DC technology was not yet mature, and the DC voltage was more complex. At this time, the Serbia youth Nicola Tesla back schoolbag, across the ocean to the idol Edison. He has an immature little suggestion - AC transmission. AC motor is simpler than DC motor and easy to change pressure. It can solve the problem of increasing transmission voltage simply, economically and reliably.
可是，这个建议被霸道总裁拒绝了。有人说是因为小爱同学没上过几天学，不懂高数，交流电对他来说有点抽象。为了阻挠交流电发展，爱迪生除了当众做交流电电死动物实验、发动媒体报道交流电事故，还促成电椅的发明——用交流电执行死刑。
However, the proposal was rejected by the overlord. Some people say that is because the students love not in a few days, do not understand the high number of alternating current for him a