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开关为什么会“咔哒”响 – 译学馆
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开关为什么会“咔哒”响

Switches are Clicky; Here's Why

Don’t ya love it when you’re learning about something
在研究某件事物时
and things, just, click?
你一定很享受豁然明朗的瞬间吧?
Like a light switch!
就像电灯的开关!
Clicky switches are pretty fun.
咔哒咔哒的开关非常有趣
But why do switches make noise?
但是为什么开关会发出声音呢?
What’s the point of all that clacking?
这种喀哒的声音有什么作用?
Well, it has to do with the fact that you’ve been lied to.
这肯定是因为你之前被人骗过
Uhh,but let’s not get too conspiratorial just yet,
但我们先不要太阴谋论
first let’s look at some of the switches that don’t click
首先 我们看一下不会发出咔哒声的开关
because there are some.
确实有些开关不发声
This electronically controlled dimming module
这个电控调光组件
turns the lights on completely silently.
可以悄无声息地把灯打开
No clicking there.
没有咔哒声
Then again, this other one that’s not a dimmer
还有另外一种 它不是调光器
makes a pronounced clicking sound.
但会发出很大的喀哒声
And I didn’t even touch it!
我甚至都没碰它!
What gives?
怎么回事?
Well, the dimming module is using a solid-state device
这个调光组件用了一种固态装置
known as a triac, to actually turn the lights on and off,
叫三段双向交流元件 来控制灯的开关
so it’s not quite what I mean by a switch.
因此把它叫做开关并不准确
This standard thing goes on or off module
而这个能打开或关闭的标准化组件
does in fact use a type of real switch to do its work,
实际上用到了真正的开关
so you hear a click.
所以你能听到咔哒声
Same with this toggle light switch.
这种拨动式开关也一样
This rocker switch.
摇杆开关同理
This rotary switch.
旋转开关也是
This lamp cord switch.
还有灯线开关
This power button.
电源键
The rocker switches on this studio light.
控制演播室灯的摇杆开关
Oh, and the big one,too.
这个大的也是
This toaster.
这个烤面包机
The mode selector on this space heater,
取暖器上的模式选择键
even its thermostat makes a distinct click.
甚至它的恒温器都会发出清脆的咔哒声
But why?
为什么呢
Why be so clicky clacky all the time?
为什么会一直咔哒咔哒响呢?
To start to answer this question,
要回答这个问题
we first need to answer a simpler question –
我们需要先回答一个更简单的问题
what is a switch?
开关是什么?
Well, a Switch is a handheld game
Switch是一个游戏掌中宝
No.
不对
A switch is a mechanism used to divert rail cars
开关是让机动车转向的机械装置
No.
也不对
A switch is the simplest mechanism
开关是能够控制电流的
that can control the flow of electricity.
最简单的机械装置
[pleasant chime]
[愉快的奏鸣]
Say you have a simple table lamp
假如你有一个简单的台灯
and want to connect it up with the power grid.
想让它通电
Well, we simply take its bare wires
我们只需要把它的裸线
and carefully touch them to these live wires,
小心地与通电导线相连
and voila!
噔噔噔噔!
Let there be light.
它就亮起来了
Now to turn the light off,
如果要把灯关掉
all we need to do is carefully pull those wires apart,
就只需要小心地把两根线分开
and hope the live ones don’t –
希望这个通电导线不要
[electric arc and explosion]
[电流泄露]
But this is pretty dangerous.
这真是相当危险
Even Edison knew that.
连爱迪生都知道
So we designed electrical sockets
因此我们设计了电源插座
which contained live wires behind an insulating barrier.
它用绝缘材料把电线挡在其后
And we designed plugs that would,
且根据你所在的国家
depending on your country,
还设计了插头
somewhere between somewhat safely and completely safely
它能在一定程度上让你安全地
allow you to make and break electrical connections.
制造或切断电流
But this isn’t the most convenient way to turn something on or off.
但这不是开关电器的最简方式
And most importantly,
更重要的是
using them that way isn’t good for your plug or your receptacle.
这对你的插头和插座不好
See, if I take this lamps and plug it into this outlet,
看 如果我把这盏灯插到这个插座上
it lights up, no problem!
它就会亮起来 没问题!
And if I simply unplug it, it goes out,
如果我直接把电源拔了 它就灭了
also without a problem.
也没什么问题
But watch what happens if I take this space heater
但再看看 如果在加热器运行时
and unplug it while it’s running.
拔掉它的插头 会发生什么
Ooh, that was quite a spark!
哇 好大个火花!
Let’s do it again!
再试一次!
Ooh!

Let’s do it again.
再来试一次
Ooh!

Big one!
好大的火花!
Let’s do that again!
继续来!
Let’s do… let’s do that again!
再来……再来一遍!
[VOICEOVER]: While this specimen continues to be amused by the sparks,
-[画外音]让这家伙津津有味地看火花吧
we’ll move on to the next jump cut.
我们进入下一个阶段
Ooh!
噢!
When the heater is running,
当加热器运行时
a lot of electricity is flowing into it through this cord.
大量的电流会进入这根电线
1,500 watts, in fact.
实际上是1500瓦
To stop that flow of current,
为了阻断电流
all we need to do is
我们需要做的就是
put an insulator between the contacts of the receptacle
在插座和插头的触点间
and the pins of the plug.
放置一个绝缘体
Which of course we can do simply by unplugging it.
当然 我们可以直接将插头拔掉
But when we unplug it,
但拔掉插头时
it doesn’t just stop the current flow right away.
它不会立马阻断电流
There’s a brief moment where
有那么一瞬间
that current manages to jump out from the outlet,
电流设法从电路中跳出
and the result is a spark.
这就会有火花
The same thing happens if you plug in the heater with it turned on,
如果在加热器开着的时候 把插头插上
right before the pins of the plug and the receptacle first make contact,
在插头和插座真正连接上的前一瞬间 也会这样
but the spark usually isn’t
但火花通常不如
as large as when an active connection is broken.
突然断开活跃电流时的大
And this is where you’ve been lied to.
这就是为什么我说你被骗了
See, when you were little,
你想 小的时候
you were probably taught about electrical conductors,
你可能学过导体
like the wires in this cord,
比如电线中的金属丝
and electrical insulators,
还学过电绝缘体
like the plastic insulation surrounding that wire.
比如环绕金属丝周围的塑料绝缘体
If you had a really nerdy teacher
如果你的老师是书呆子
you might have learned about semiconductors,
你可能还学了半导体
but lots of us were sorting things into the two categories of
但是我们当中很多人都将把事物分成
insulators, and conductors.
绝缘体和导体两类
The lie is that,
谎言是
just like most things in the real world
就像现实世界中的大多数事物
the electrical conductivity of any given substance exists on a spectrum.
任何事物的导电性都有一定的范围
Everything conducts electricity
只要你努力尝试
when you try hard enough.
什么东西都能导电
Even air.
哪怕是空气
Now we rely on the resistance of air all the time!
而我们还在一直利用空气的阻力!
Electrical transmission lines are typically bare aluminum
输电线路通常是裸露的铝线
and are held up in the air by stacks of insulating discs.
通过堆叠的绝缘圆片固定在空中
The higher the voltage of the line
导线的电压越高
the more of these discs you need
需要的圆片就越多
because even they aren’t perfect insulators.
因为即便这些圆片 也不是完美的绝缘体
Nothing’s a perfect insulator!
没有完美的绝缘体!
And that’s the problem.
这就是问题所在
Air’s pretty good,
空气是很好的绝缘体
and when you unplug something from an electrical outlet,
当你从电源插座上拔下插头时
you do disconnect it from the power grid
你就切断了电源
and stop the flow of electricity to it,
电流也被隔断了
precisely because there’s air now between the pins of the plug
这是因为插头的插针和插座中的导体间
and the conductors in the receptacle.
有了空气
But,when you pull that plug out of the wall,
但当你从墙壁上拔下插头时
there will be a brief moment when there’s
会有一个短暂的时刻
only a tiny bit of air between the plug and the socket,
在插头和插座之间 只有一点点空气
and this is not good.
这样可不好
When those contacts are close but not quite touching,
当这些触点很近但相互不接触时
the air gap is so small that the breakdown voltage,
由于气隙太小 以至于击穿电压
that’s the voltage at which an insulator fails to stay an insulator,
即能使绝缘体无法发生作用的电压
is lower than the voltage of the electrical supply.
会低于电源电压
This means that the current will actually jump the gap,
这意味着电流实际上会跳开该间隙
and this creates an arc discharge.
从而产生了电弧放电
That’s the spark you see here.
也就是你看到的火花
Now on its own this isn’t particularly bad.
就其本身而言 这并不是特别糟糕
Thanks to the fact that we use AC power,
由于我们使用的是交流电源
the voltage crosses the zero point 100 or 120 times per second
电压每秒通过0.100或0.120次
so that arc will usually go out nearly immediately,
所以电弧通常会马上灭掉
though it should be noted that arcs can be sustained on AC power.
但需要注意 电弧可以在交流电上持续存在
More importantly,
更重要的是
the breakdown voltage of any insulator, including air
包括空气在内的所有绝缘体的击穿电压
is a function of how thick it is,
都与绝缘体厚度有关
so once the contacts are just a millimeter apart,
所以一旦触点之间哪怕仅相隔一毫米
that arc will generally be unsustainable.
电弧通常就难以为继
But here’s the problem.
但还有一个问题
That arc is hot. Very, very hot.
电弧很热 非常非常热
So hot, in fact,
事实上 它太热了
that it can burn the ends of the plug and the socket.
甚至可以烧毁插头和插座的两端
So we don’t want to rely on pulling the plug
因此 我们不想依赖把插头
out of the socket to stop current flow.
从插座中拔出来的方式阻断电流
What do we do instead?
我们该怎么办
We use a switch.
我们用开关
All the switch does is create a break in a circuit.
开关所做的就是在电路中产生一个断路
There are many different types of switches
尽管开关有很多种
but they all do fundamentally the same thing.
但是它们都起着相同的作用
There are two electrical contacts,
有两个电触点
and they’re either touching, or they’re not.
它们要么接触 要么不接触
If they touch, current can flow.
如果它们接触 电流就会通过
And if they don’t touch, current can’t.
如果不接触 电流就不能通过
But then, switches do the same thing as unplugging it!
而开关的作用与拔掉插头的作用相同
Don’t they have to worry about arcing?
它们就不用担心电弧吗?
Yes, in fact even more so.
不 事实上它们更担心这一点
Electrical arcs damage electrical contacts in various ways,
电弧会以各种方式损坏电触点
but among the most significant ones
但最重要的是
is that the contacts eventually… melt away.
触点最终……会融化
See, each time there’s an arc,
每次出现电弧时
that plasma is so hot
等离子体就会变得非常热
that the surface of the contact briefly melts,
以至于触点表面会短暂融化
and that material can sputter off of it.
它可能会从其上溅射出来
Additionally, the high temperature can cause corrosion of the contacts,
此外 高温还会导致触点腐蚀
and you get lovely issues like carbon buildup
导致一些恼人的问题
which increases the electrical resistance of the contacts,
比如积碳 它会增加触点的电阻
and that’s not good.
这并不好
Even better, if the arcing is bad enough,
更糟糕的是 如果电弧放电严重
and the surface of the contacts get hot enough,
触点的表面变得过热
they can weld together and get stuck closed!
它们可能会焊接在一起并被卡住
I guess that light’s on forever now…
我想那盏灯会永远亮着了……
Since the contacts in a switch are generally pretty small,
由于开关中的触点通常很小
we want to minimize the arcing that can happen because,
我们希望尽量减少电弧的发生
well, an arc will warm them up quickly
因为电弧会使它们快速升温
and cause all those problems I was just going on about.
从而引发我刚才提到的问题
And how do we do that?
那我们该怎么做?
Why, with speed!
速度是关键!
Remember that household voltages are low enough that
记住 家庭电压很低
an arc generally can’t be sustained
因此哪怕触点之间只相距一毫米
once the contacts are just a millimeter apart.
一般就无法维持电弧
So, if you get them apart quite quickly,
所以如果你快速地把它们分开
any arc formation that does occur will be very brief,
产生的电弧会是非常短暂的
and unlikely to cause significant damage.
且不太可能造成重大损害
And that is why switches click.
这就是为什么开关会响
[click]
[咔哒]
Switches are designed with mechanisms
开关的设计原理是
to ensure the contacts open and close very quickly,
确保触点的快速打开和闭合
quickly enough to prevent an arc from lasting more
通过快速操作 防止电弧持续超过
than maybe a millisecond or so.
一毫秒左右的时间
Effectively, the contacts are meant to slam together
实际上 这些触点就是为了
and then get yanked apart,
容易控制开合设计的
and that makes an audible click.
这个动作形成了我们听到的咔哒声
The mechanisms that accomplish this are often ingeniously simple.
实现这一目标的原理通常非常简单
Many times,
很多时候
it’s just a spring cleverly integrated into a pivot.
它就是巧妙地在支点上装一个弹簧
Let’s take a look at a simple household rocker switch.
让我们看一个简单的家庭摇杆开关
This switch is nice and clicky.
这个开关很好用且有咔嗒声
[repetitive rapid clicking]
[重复的快速咔哒]
Who needs a fidget clicker when you can just
如果你可以很轻松地从五金店买到这个
run to the hardware store and get one of these?
谁还会专门买个点击解压器呢
This design is almost devilishly simple.
这个设计非常简单
Below the faceplate are three pieces of brass,
面板下面是三块铜片
two of which are the same ones you attach wires to on the outside.
其中两个是你用来连接导线的
The smaller one holds an electrical contact,
较小的那只控制电触点
and the larger one serves as a pivot point
较大的那个作为支点
for a small swinging piece that holds the other contact.
用于固定另一个触点的小弹片
If there’s a torque applied to the swinging piece in this direction
如果有扭矩从这个方向作用在弹片上
the contact does not touch the other one,
则该触点不会与另一触点接触
and no current can flow through the switch.
就不会有电流通过开关
But apply a torque in the other direction,
但向另一个方向施加扭矩
and now the contacts touch.
触点就会接触
Current flows into the switch through this terminal,
电流会通过这个端口流入开关
through the basket thing,
通过这个小盒子
into the swinging thing, through the two contacts,
再通过弹片和两个触点
and out the other terminal.
从另一端流出
All it takes to ensure the swinging contact moves quickly is a spring.
弹簧是确保弹片触点快速移动的关键
See the rocker paddle that you touch is
你碰到的摇杆桨
in fact the same thing moving the contact.
实际上是使触点移动的东西
These grooves hold onto the edge with a little play,
通过一些调整 这些凹槽会固定在边缘上
and when the rocker rocks back and forth,
当摇杆来回晃动时
so does the contact below.
下面的触点也会如此
But thanks to the spring,
但是因为有弹簧
the rocker, and more importantly the contact
摇杆 及更重要的触点
wants to stay in either position.
才能停在任意位置
The spring gets increasingly compressed
当摇杆运动到顶点
as the rocker meets the apex,
弹簧不断被压缩
and once it passes it…
一旦摇杆越过顶点……
bam,
砰的一声
the spring expands
弹簧就会展开
and pushes the contact in the other direction.
然后将触点推向另一个方向
The result is a swift action in both directions,
结果是两个方向都迅速动作
minimizing arcing.
从而最大程度地减少了电弧放电
Pretty clever.
很聪明的设计
Unfortunately though,
尽管
this switch design isn’t perfect.
这种开关设计并不完美
In fact, many, if not most,
事实上 不说绝大多数
switches on sale today aren’t.
至少许多在售的开关都不完美
See, you can actually move the contact a bit
实际上在弹簧移动前
before the spring takes over.
触点能稍微动一下
If you carefully apply pressure on the switch,
如果你轻轻地按动开关
you’ll see that the light goes out
你会看到灯先灭了
before it clicks into the off position.
然后才发出咔嗒一声
Listen carefully and you can actually hear arcing going on inside the switch.
仔细听 你可以听到开关内部电弧的声音
[faint arcing sound]
[微弱的电弧声]
This… isn’t really great,
这不太妙
especially if you have a lot of lights on the circuit you’re controlling.
尤其是当你控制的电路上有很多灯时
In fact you can see on these contacts
实际上 你可以在这些触点上看到
that they have been slightly damaged,
它们受到了轻微的损坏
and this isn’t a very old switch.
而这个开关还不算旧
I know because I installed it myself.
我知道因为 那是我亲自安装的
Granted, most people don’t turn the lights on and off like this.
当然 大多数人不会像这样又开又关
If you do it like a normal person,
如果你正常使用
then the contacts are swiftly moved and arcing is minimal.
触点就会快速移动 且电弧最短
Still, it annoys me
但我还是觉得闹心
that it’s even possible to damage the switch at all.
因为开关居然会因此损坏
Many switch designs, like these lamp cord switches,
许多开关的设计 比如这个灯绳开关
are simply impossible to hold in
根本不可能停留在
a half-on, half-off state.
半开半关的状态
Sure, they’re not designed to carry
当然 它们的设计初衷不是
the current of a normal light switch,
承载普通电灯开关电流
but I bet these guys rarely ever fail from bad contacts.
我敢打赌 它们很少因接触不当而损坏
And normal switches can be made impossible to abuse.
正常开关的设计也可以这样避免不恰当使用
The house I grew up in was quite old,
我小时候住的房子很旧
and a few rooms had toggle light switches that
有几个房间用的是拨动式开关
you could actually move nearly completely into the opposite position
当开关差一点点要被拨到另一侧时
before the internal mechanism opened or closed the contacts
开关里的触点才会被触发
with a very loud clack.
同时发出很大的噼啪声
[a very loud clack]
[很响的一声]
Those switches were in service for 50 or 60 years
这些开关已经用了五六十年
and likely still are.
而且还可能继续使用
Granted, they were only controlling a single light
当然除了一点 如果没记错的话
in all but one case, if memory serves
它们只能控制一盏灯
so they weren’t ever under much electrical stress,
所以它们不会承受太大的电压力
and they required much more force
而且比起现代开关
to use than modern switches,
它们用起来更费力
which is probably why that style went out of favor.
这可能是那种风格不再流行的原因
But, this paddle-style dimmer switch has a mechanism that
但这款拨片式调光开关内有一种机制
prevents partial making and breaking of the contacts
可在不太费力的情况下
without requiring significant force.
防止触点局部闭合及断开
You can see that even if I use my two thumbs
可以看到 即使我用两个拇指
on both sides of the switch and very,
在开关两侧非常
very slowly move the paddle,
非常缓慢地移动拨片
the lights only go on and off
灯也只有当内部机械装置运动
with the click of the internal mechanism.
并发出咔嗒声后才能点亮和熄灭
This design here is what I’d call ideal,
这就是我所说的理想设计
and it proves that easy-to-use switches can
它证明了 方便好用的开关也可以
still be made with a fast, clicky, abuse-proof mechanism.
反应快 声音清脆 且避免不当使用
So if you’re shopping for a light switch at a hardware store
所以如果你要在五金店买电灯开关
tactile feel of the switch does actually matter when it comes to switch longevity.
开关的触感确实对开关的使用寿命有影响
A nice, solid snap makes me more confident
比起平缓无声的动作
than a smooth, quiet movement.
快速又结实的弹响会让我更放心
This cheap toggle switch is what I’d consider awful.
我觉得这种廉价的摇杆开关很糟糕
The toggle moves smoothly without much resistance at all,
摇杆移动平缓 且阻力不大
and the contact is actually broken
开关都还没移到顶点
when the switch has barely moved out of its resting position.
触点实际上就已经断开了
It actually requires conscious effort to ensure
你需要很注意
the contacts are quickly moved apart, and
才能确保触点迅速分开
I doubt this switch would last more than a decade
如果这个开关控制了好几个灯
on a circuit with more than a few lights.
我不认为它能使用超过十年
In fact, it’s not even fair to say
实际上 我们甚至不能说
that this switch actually clicks.
这个开关能发出咔哒声
It more or less thuds.
它更像是砰的一声
Any switch that’s designed to interrupt even a modest current flow should,
在我看来 哪怕通过的电流很弱
in my opinion,
好的开关设计
have a nice audible click.
都应该发出能清脆可闻的咔嗒声
That plug-in thing-goes-on module?
刚提到的插入式模块?
It got a relay in it.
它里面装有继电器
Relays are electromechanical devices
继电器是一种机电设备
that control large currents with small currents.
它通过小电流控制大电流
Essentially they’re a switch with some sort of external control.
本质上它们是带有外部控制的开关
In this case, the small computer inside here
在这种情况下 里面的小型计算机
will turn on the relay when it’s been asked to,
将在需要时打开继电器
and click, the light goes on.
咔哒一声 灯就亮了
The contacts in a relay are closed via an electromagnet,
继电器中的触点通过电磁铁闭合
and are held open with a spring.
并通过弹簧撑开
And, as luck would have it,
而且 幸运的是
this simple arrangement means the switch opens and closes quickly.
这种简单的排列意味着开关可以快速打开和闭合
And so, it clicks.
因此 它会发出咔嗒声
Fun fact!
有趣的是
When we need to automatically control very high current loads,
当我们需要自动控制非常大的电流负载时
we use what are essentially large relays
我们使用的东西叫接触器
but we call them contactors.
但本质上是大型继电器
Contactors often just use air to break the circuit like any other switch.
和其它开关一样 接触器会用空气阻断电流
But when we get into high voltage applications,
但是当我们进入高压应用时
the contactor might be contained in a vacuum,
接触器可能被装在真空中
and in really high voltage applications
而在超高压应用中
like in power grid substations,
如电网变电站中
you might find switches and circuit breakers
你可能会发现在一些六氟化硫中
inside a volume of sulfur hexafluoride,
发现开关和断路器
which is an incredibly good insulator and
六氟化硫是非常好的绝缘体
and this is in fact the primary commercial use of SF6.
实际上这就是SF6的主要商业用途
Now, not all switches need to click.
并不是所有的开关都要发出咔哒声
Switches that don’t carry a lot of current,
不带很多电流的开关
like the clicky buttons on your mouse,
如鼠标上的点击按钮
don’t need to click at all
根本就不用有声音
because there’s not gonna be any arcing going on in there.
因为那里不会有电弧
They click mainly because that style of switch
它们会响主要是因为
is designed to provide a lot of tactile feedback.
这种开关旨在提供许多触觉反馈
And actually, a very clicky switch can be a disadvantage
实际上 如果电子设备的开关很响
in digital devices,
反而是缺点
because now you might need to implement some sort of debouncing.
因为你可能要添加防抖功能
But that’s beyond the scope of this video.
但这超出了本视频的范围
So, now you know why switches click.
现在你知道为什么开关会咔哒响了
They’re really just prolonging their life.
这是在延长使用寿命
And if you want to prolong the life of the switches in your life even more,
如果你想要更好地延长开关使用寿命
be sure you always give them a good flick. Or, poke.
就确保你按或戳的时候要快
Since many modern designs kinda make you a part
由于许多现代设计都使你成为了
of the contact closing and opening action,
触点闭合和断开动作的一部分
you can and should click to your heart’s content.
你可以 也应该好好选开关
Thanks for watching!
谢谢收看!
And thank you to the fine folks supporting this channel through Patreon.
感谢Patreon对这个频道的支持
I really do appreciate your support.
非常感谢你的支持
If you’re interested in joining these people
如果你有兴趣与这些人一起
in supporting the channel,
支持该频道
you can check out the link at the end screen, or in the description.
你可以查看屏幕下方或描述中的链接
Thanks for your consideration, and I’ll see you next time!
谢谢你的关注 下次再见!
♫ illuminatingly smooth jazz ♫
[明快舒缓的爵士乐]
Nope.

I messed up.
我搞砸了
I thought this would go quickly, it’s not going quickly.
我还以为很快能拍完 结果不行
So if you get them apart quickly…
如果你迅速把它们分开……
[clears throat]
[清嗓子]
That was going well, but then it wasn’t.
刚开始发挥不错 后来崩了
Wrong pronunciation!
发音错误
[struggling sounds]
[挣扎的声音]
No no no, that’s the wrong way!
不不不 那样不对!
[more struggling sounds]
[更多挣扎的声音]
[also the tripod is creaking, that’s fun]
[还有三脚架吱吱作响 这很有趣]
Now… no I don’t like how I did that eith…
不行 我不喜欢我的表现
well, ugh. Cra.. that might have been, erm, nevermind.
嗯 啊 刚刚……唔 算了

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译制信息
视频概述

你是否有好奇过为什么开关会发出“咔哒”声?《科技连接》来揭秘!

听录译者

收集自网络

翻译译者

ericaeureka

审核员

审核员MS

视频来源

https://www.youtube.com/watch?v=jrMiqEkSk48

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