标签: jack

在硬件设计时，经常会涉及音频的Audio Jack部分，Audio Jack的原理图库也是多种多样，经常让人困惑不解。最近看到知名连接器厂家CUI DEVICES的一篇文章 Understanding Audio Jack Switches and Schematics，觉得写得不错，尤其是图解很是简单明了，简单翻译记录下，也可以去翻看原文： https://www.cuidevices.com/blog/understanding-audio-jack-switches-and-schematics Audio Jack原理图 Audio Plug也就是音频插头可以由2-6或者更多导体构成，每段导体有不同的名字，通常为Sleeve、Tip、Ring等。下面以3段式的立体声连接器为例，下面是基本的原理图，不包括开关： 在理解Plug和Jack的连接关系时，可以想象下，将Plug从左到右插入Jack，如下图所示： 上图解释了Jack原理图库中信号线的含义。 Audio Jack开关 Audio Jack除了信号中，还通常带有开关。下面在端子2（tip）增加一个开关10。这个开关如下面的左图所示， 在未插入状态时通常为闭合状态。端子10和端子2直接连接，因为这个开关位于tip位置，所以通常被称为tip switch。 现在我们再次想象plug从左到右插入，当tip和端子2接触时，将端子10推开，两者断开连接。 与之类似，多个开关可以存在于不同触点上，下面是个4插头的例子， 有3个开关位于tip，ring1和ring2位置上。 这个看起来很复杂，但原理和单个开关相同，只是多个两个类似的开关。 到目前为止，我们看到的开关都是通常闭合的，也有一些是通常断开的、SPDT、DPDT。这些开关中许多是和音频信号隔离，用于其他控制电路。 Audio Jack开关应用 应用场合决定了选用那种Audio Jack以及是否带开关。如果只是需要简单的插入耳机并听音乐，并不需要audio jack带有开关。如果需要在speaker和headphones之间切换，检测plug是否插入，使用插入的plug控制电路的其他部分，或者使用音频混音板，那就需要开关功能。 在speaker和headphones之间切换音频 下图中的第一个，plug没有插入，端子10和11两个开关闭合，音频信号直接传送到speaker上，在第二个图中，plug插入后，端子10和11被打开，音频进入headphones. 检测Plug插入 相似的方式，当plug断开端子10时，可以检测plug插入。 控制电路中独立于音频的其他位置 下图中的4-6独立于音频信号1-3，这里利用了SPDT开关，在未插入时，4和5连接在一起，在插入后，5和6连接在一起。这就利用插头在功能A和B之间切换。

I just learned a whole bunch of new "stuff" that's why I'm currently as happy as... well, something that's very happy. It all came about when, a week or so ago, I started re-watching all of the new Doctor Who episodes starting with "Rose" from 2005. In fact, I was watching one last night where someone mentioned "The Union Jack" (the national flag of the United Kingdom) and Rose noted that it should more properly be called "The Union Flag"; also that "Union Jack" should only be used if the flag was flying on one of Her Majesty's Warships. Well, I'm always interested in discovering something new, so a few minutes ago I bounced over to the Wikipedia to learn more ( Click Here to visit the Union Jack page on the Wikipedia). From there I became embroiled in a delightful morass of terminology, including works like Blazon , which is a formal description of a coat of arms, flag, or similar emblem, from which the reader can reconstruct the appropriate image. As the Wikipedia says: The visual depiction of a coat of arms or flag traditionally has considerable latitude in design, while a blazon specifies the essentially distinctive elements; thus it can be said that a coat of arms or flag is primarily defined not by a picture but rather by the wording of its blazon. Blazon also refers to the specialized language in which a blazon is written, and, as a verb, to the act of writing such a description. This language has its own vocabulary, grammar, and syntax (rules governing word order), which becomes essential for comprehension when blazoning a complex coat of arms. As you may or may not know, the Union Jack is actually formed from three major elements: The red St. George's Cross , the white diagonal St. Andrew's Cross (not to be confused with the white "fimbriation"), and the red diagonal St. Patrick's Cross (the blue parts are actually the background, which – according to the Wikipedia entry for Blazon – is actually referred to as the "field").   I don't know why, but I love all of this stuff, such as learning the meaning behind word like fimbriation , which I now know refers to small stripes of colour (technically called "tincture" in this sense in heraldry) placed around "common charges" or "ordinaries." This is usually in order to make the "common charges" stand out from the "field" (background), but may be used "just because the designer felt it looked better," or to avoid what would otherwise be a violation of the heraldic "rule of tincture." In order to explain what I mean, the "fimbriation" of the "ordinaries" is highlighted in yellow in the following depiction of the Union Jack:     Quite apart from anything else, this is also the first time I really understood how to tell whether the Union Jack is being flown the right way up, or not:   The correct way to fly the Union Jack (top) and the incorrect way (bottom).   The thing is that the Union Jack does not have reflection symmetry due to the slight pin-wheeling of the St Patrick's and St Andrew's crosses (technically the "counterchange of saltires"). The end result is that there is a right side up and a wrong side up. To fly the flag correctly, the white of St Andrew should be above the red of St Patrick in the "upper hoist canton" (the quarter at the top nearest to the flag-pole). I remember first hearing about this as a kid. I was watching an episode of some cowboy program like Bonanza or High Chaparral or Gunsmoke (I forget which). The bad guys had taken an old Englishman captive in his cabin, but our heroes worked out that something was wrong because he'd hoisted his Union Jack upside down. Now that I understand, I will certainly keep a watchful eye open whilst on my travels so as to quickly detect if any skullduggery is afoot. I tell you, you can really get sucked into all of this stuff. For example, do you know why the canton of the flag of Hawaii contains the Union Flag of the United Kingdom, prominent over the top quarter closest to the flag mast (this is the only U.S. state flag to feature the Union Flag)?   The flag of Hawaii   If you wish to learn why this should be, all I can say is Click Here to visit the appropriate page on the Wikipedia, but don't blame me if you get sucked into the ensuing "Informational vortex of no return"...