笔记本电源适配器为什么总坏_为什么某些交流适配器和电源会发出啸叫声？

笔记本电源适配器为什么总坏

why-do-some-ac-adapters-and-power-supplies-generate-a-whining-noise-00

Most of the time our AC adapters and power supplies tend to be quiet, but what does it mean when one makes a whining noise? Should you be concerned? Today’s SuperUser Q&A post has the answers to a worried reader’s questions.

大多数时候，我们的AC适配器和电源往往比较安静，但是当发出嘶哑的声音时，这意味着什么呢？你应该担心吗？今天的“超级用户问答”帖子为读者提供了一个令人担忧的问题的答案。

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

今天的“问答”环节由SuperUser提供，它是Stack Exchange的一个分支，该社区是由社区驱动的Q＆A网站分组。

Photo courtesy of Bart Everson (Flickr).

图片由Bart Everson(Flickr)提供。

问题 (The Question)

SuperUser reader Rishat Muhametshin wants to know why some of his AC adapters and power supplies make a whining noise:

超级用户读者Rishat Muhametshin想知道为什么他的某些AC适配器和电源会发出嘶嘶声：

I have many different AC adapters and power supplies for a variety of devices, ranging from small 5V/1A USB chargers to laptop power adapters and desktop PSUs. However, I often hear a whining noise from some of these power supplies. This happens most often when they are not connected to a device or otherwise in use, and stop making noise when I connect a device that is not fully charged.

我有许多用于各种设备的AC适配器和电源，从小型5V / 1A USB充电器到笔记本电脑电源适配器和台式机PSU。但是，我经常听到其中一些电源发出刺耳的声音。当它们未连接到设备或以其他方式使用时，这种情况最常发生，而当我连接未完全充电的设备时，则停止发出噪音。

Why do some AC adapters and power supplies make this whining noise? Why do some not make this noise? Is there anything that I can do to suppress it?
为什么有些交流适配器和电源会发出这种啸叫声？为什么有些人不发出这种声音？有什么我可以抑制的事情吗？

Why do some AC adapters and power supplies make a whining noise?

为什么有些交流适配器和电源会发出嗡嗡声？

答案 (The Answer)

SuperUser contributors DragonLord and Daniel R Hicks have the answer for us. First up, DragonLord:

超级用户贡献者DragonLord和Daniel R Hicks为我们提供了答案。首先，DragonLord：

Most power conversion devices contains coils, such as transformers or inductors. These components use electromagnetism to convert AC main power to low-voltage DC power. The varying magnetic fields generated by these components can cause them to physically vibrate at high frequency, resulting in a high-pitched noise.

大多数电源转换设备都包含线圈，例如变压器或电感器。这些组件使用电磁将交流主电源转换为低压直流电源。这些组件产生的变化的磁场会导致它们在高频下发生物理振动，从而产生高音调的噪声。

Most modern AC adapters are switched-mode power supplies. The internal switching frequency of an SMPS is typically low when unloaded and increases with a load (up to a certain point depending on the design). The no-load frequency is often low enough to be within the human hearing range.

大多数现代交流适配器都是开关电源。卸载时，SMPS的内部开关频率通常较低，并随负载而增加(取决于设计，直至特定点)。空载频率通常足够低以至于在人类的听力范围内。

In addition, in low or no-load situations the PWM (Pulse Width Modulation) used to regulate voltage at the inverter stage will be at a low duty cycle and create a “spikey” output profile which is more prone to causing vibration in coils, and the transformer itself will tend to vibrate as well. Together, these can lead to audible noise especially in cheaper units which fail to suppress this noise.

此外，在低负载或空载情况下，用于调节逆变器级电压的PWM(脉冲宽度调制)将处于低占空比，并产生“尖峰”输出曲线，该曲线更容易引起线圈振动，变压器本身也容易振动。这些因素加在一起会导致可听见的噪声，尤其是在无法抑制这种噪声的廉价设备中。

Under a load, a properly functioning SMPS should operate at a frequency well above the human hearing range, typically 50 KHz or higher (although some older designs operate at 33 kHz). However, the same noise can occur under a load with a poorly designed or defective power supply as the coils may vibrate under electrical stress at a sub-harmonic frequency.

在负载下，功能正常的SMPS应在高于人类听力范围的频率(通常为50 KHz或更高)下运行(尽管某些较旧的设计以33 kHz的频率运行)。但是，在设计不良或电源故障的负载下也会产生相同的噪声，因为线圈可能会在电应力作用下以次谐波频率振动。

This is why you sometimes see a “glue” of sorts on coils inside electronic devices. The glue helps reduce the vibration and noise the coils generate during normal operation. Of course, this means that a user can apply glue onto coils using a glue gun to suppress coil whine—and yes, people have done this successfully with PC motherboards, graphics cards, and power supplies. However, you generally cannot do this easily on small wall chargers of the sort you mentioned without risking damage to the charger or exposure to potentially dangerous voltages.

这就是为什么您有时会在电子设备内部的线圈上看到各种“胶水”的原因。胶水有助于减少线圈在正常运行期间产生的振动和噪声。当然，这意味着用户可以使用胶枪将胶水涂在线圈上，以抑制线圈发出的嗡嗡声。是的，人们已经使用PC主板，图形卡和电源成功完成了此操作。但是，您通常无法在提到的那种小型壁式充电器上轻松进行此操作，而又不会冒损坏充电器或暴露于潜在危险电压的危险。

In conclusion, a whining noise is not necessarily a sign of trouble in cheaper wall chargers when they are unloaded. However, a computer PSU or laptop charger that generates coil noise, especially when under a load, may be defective and you may want to consider replacing it.

总之，在便宜的壁式充电器卸下时，发出嘶嘶声并不一定是麻烦的迹象。但是，计算机PSU或笔记本电脑充电器会产生线圈噪声，尤其是在负载下时，可能是有缺陷的，您可能需要考虑更换它。

More information on coil noise can be found in this Wikipedia article.
有关线圈噪声的更多信息，请参见此Wikipedia文章。

Followed by the answer from Daniel R Hicks:

随后是Daniel R Hicks的回答：

A coil of copper wire without any “core” metal plates can be made to whine. As the magnetic field increases and decreases (generally about a thousand times a second), the force of the field causes the dimensions of the coil to change slightly, and this vibration leads to a whining sound. Even the wires on a printed circuit board can whine (slightly) under the right circumstances.
可以制造没有任何“芯”金属板的铜线线圈。随着磁场的增加和减少(通常每秒大约一千次)，磁场的力使线圈的尺寸略有变化，并且这种振动会导致发出嘶嘶声。在正确的情况下，甚至印刷电路板上的电线也可能(轻微)发牢骚。

Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

有什么补充说明吗？在评论中听起来不错。是否想从其他精通Stack Exchange的用户那里获得更多答案？在此处查看完整的讨论线程。