nodemcu控制开关电灯
If there are lights in your house that can be controlled from two different light switches (as opposed to just one), then the light is commonly referred to as a three-way light, and the switches are referred to as three-way light switches. Here’s how they work.
如果您家中的照明可以通过两个不同的照明开关(而不是一个)来控制，则该照明通常称为三向照明灯，而这些开关称为三向照明灯开关。 这是他们的工作方式。
If you know anything about circuitry, then you at least probably know that an on/off switch is perhaps the simplest piece of circuitry there is. But once you add in a second switch to control the same object, things can get a bit complicated.
如果您对电路一无所知，那么您至少可能知道通/断开关可能是其中最简单的电路。 但是，一旦添加第二个开关来控制同一对象，事情就会变得有些复杂。
电灯的工作原理 (How a Light Switch Works)
Before explaining how three-way light switches work, it’s important to know how a regular light switch works. These are called single-pole light switches, and they can turn on or off a light fixture from a single location. These are the most common types of light switches and are mostly found in bedrooms, bathrooms, and other simple room layouts where you would really only need one light switch.
在解释三向电灯开关的工作原理之前，了解常规电灯开关的工作原理很重要。 这些被称为单极照明开关，它们可以从一个位置打开或关闭灯具。 这些是最常见的电灯开关类型，通常在卧室，浴室和其他简单的房间布局中使用，而您实际上只需要一个电灯开关。
Note: In the diagrams below, the neutral “return” wires and ground wires aren’t shown in order to make the diagrams as easy as possible to understand. If you’re worried about this, just know that the neutral “return” wire in the circuit doesn’t connect to any of the switches and simply continues on, whereas ground wires will connect to the green screw on every switch.
注意：在下面的图中，未显示中性的“返回”线和地线，以便使图尽可能容易理解。如果您对此感到担心，只需知道电路中的中性“返回”线没有连接到任何开关，而只是继续导通，而地线将连接到每个开关上的绿色螺钉。
In a traditional wiring setup with a single light fixture and a single switch, you have a hot wire coming in from the electrical panel that supplies the power to the light fixture. However, a light switch is installed in line with that hot wire. So when the light switch is off, it breaks the connection of the hot wire so that power can’t get to the light fixture. When the switch is turned on, the hot wire is reconnected, thus supplying power to the light fixture.
在具有单个灯具和单个开关的传统接线设置中，您会从配电盘中插入一条热线，为灯具供电。 但是，电灯开关与该热线对齐安装。 因此，当电灯开关关闭时，它会断开热线的连接，从而使照明装置无法通电。 当开关打开时，热线会重新连接，从而为灯具供电。
添加第二个电灯开关 (Adding in a Second Light Switch)
Things get a bit complicated when you introduce a second light switch into the mix, but it’s still pretty simple once you know how it all works.
当您在混音中引入第二个电灯开关时，事情会变得有些复杂，但是一旦您知道其工作原理，它仍然非常简单。
A three-way light switch is different than a traditional single-pole light switch, as it contains an extra screw to connect an extra wire. This is known as the “common” screw and it’s usually black (instead of brass or silver). Another dead giveaway of a three-way switch is the absence of “On” and “Off” markings.
三向电灯开关与传统的单极电灯开关不同，因为它包含一个用于连接额外电线的额外螺钉。 这被称为“普通”螺丝，通常为黑色(代替黄铜或银色)。 三通开关的另一个致命缺点是没有“ On”和“ Off”标记。
This is why whenever you need to replace a light switch in your house, it’s important that you get the right kind of light switch, since you can’t use a single-pole switch in a three-way circuit.
这就是为什么每当需要更换房屋内的电灯开关时，重要的是要获得正确的电灯开关 ，因为不能在三路电路中使用单刀开关。
The diagram below provides a simple layout of a three-way light setup, and you can see the red wire is the extra wire that’s needed to make it all happen (conveniently enough, red wire is normally used in real life in three-way circuits as well).
下图提供了三路灯光设置的简单布局，您可以看到红色导线是实现所有步骤所需的多余导线(足够方便的是，红色导线通常在现实生活中用于三路电路中)以及)。
How it works is that the hot wire coming in from the electrical panel is connected to the common screw of the first light switch in the circuit.
它的工作原理是将来自配电盘的热线连接到电路中第一个电灯开关的普通螺钉上。
On the other side of this switch are two brass screws. The “traveler wires” (a.k.a. the wires that connect the two light switches to each other) attach to these two screws, and it doesn’t matter which of the two screws they each connect to.
在此开关的另一侧是两个黄铜螺钉。 “旅行电线”(也就是将两个电灯开关相互连接的电线)固定在这两个螺钉上，无论它们分别连接到两个螺钉中的哪个螺钉上，都没有关系。
On the other switch, the hot wire that continues on to the light fixture attaches to the common screw. And as with the previous switch, the two traveler wires will connect to the two brass screws (again, in no particular order).
在另一个开关上，延续到灯具的热线连接到普通螺钉上。 与之前的开关一样，两条钢丝绳将连接到两个黄铜螺丝(同样，没有特别的顺序)。
This wiring setup uses the two traveler wires to allow for either light switch to control the light fixture. Not only that, but this also allows you to turn on the light from one switch and turn it off from the other switch. For example, the diagram below shows the inside of each switch and their “on/off” positions.
此接线设置使用两条钢丝绳，以允许任何一个电灯开关控制灯具。 不仅如此，这还允许您从一个开关打开灯，而从另一个开关关闭灯。 例如，下图显示了每个开关的内部及其“开/关”位置。
Currently, each switch is in a different state, but thanks to the top traveler wire, the circuit is still complete and the light is on. Flipping either of the switches will break the circuit and turn the light off. However, if you were to flip the other switch, then the circuit would use the red traveler wire this time and the light would turn back on.
当前，每个开关处于不同的状态，但是由于使用了顶部的钢丝绳，所以电路仍然完整且灯一直亮着。 翻转任何一个开关都将断开电路并关闭灯。 但是，如果您要拨动另一个开关，则电路这次将使用红色的钢丝绳，并且指示灯将重新点亮。
It sounds complicated at first, but as you’ve now discovered, it’s actually pretty simple.
乍一看听起来很复杂，但是正如您现在所发现的，它实际上非常简单。
超越三路电灯开关 (Beyond Three-Way Light Switches)
Three-way lights are fairly common in a lot of larger houses, but you might also find four-way, or even five-way lights, in some houses.
三通灯在许多较大的房屋中相当普遍，但是在某些房屋中您可能还会发现四通甚至五通灯。
Four-way circuits are just a tad different than three-way circuits, mostly since the light switch that you add in has to be a four-way switch rather than just another three-way switch. A four-way switch has an extra common screw to bring the total number of screws up to four: two common screws and two brass screws (not counting the ground screw).
四路电路与三路电路稍有不同，主要是因为您添加的灯光开关必须是四路开关，而不是另一个三路开关。 四向开关具有一个额外的普通螺钉，可以使螺钉总数增加到四个：两个普通螺钉和两个黄铜螺钉(不包括接地螺钉)。
This allows for the two traveler wires to travel through the four-way switch and onto the next switch in the circuit, which means four wires will connect to this switch rather than just three.
这允许两条走线穿过四向开关并到达电路中的下一个开关，这意味着四根电线将连接到该开关，而不仅仅是三根。
From there, you can add on as many four-way switches as you want, just as long as there are three-way switches on either end. You shouldn’t have to worry about anything more than a four-way circuit, though, as five-way circuits and higher are fairly uncommon in most residential households.
从那里，您可以根据需要添加任意数量的四向开关，只要两端都有三向开关即可。 不过，您不必担心四通电路，因为在大多数居民家庭中，五通及以上电路并不常见。
翻译自: /332814/how-three-way-light-switches-work/
nodemcu控制开关电灯
