You can support this channel on Patreon! Link below
Click clack I was taken aback. Wonderin’ ‘bout those switches of light, yeah.
Let’s find out what the point is of all that clacking, shall we?
Hey! Here are some fun links!
Technology Connections on Twitter:
https://twitter.com/TechConnectify
The TC Subreddit
https://www.reddit.com/r/technologyconnections
Technology Connections 2 (the channel where I sometimes talk about stuff and generally don’t prepare for anything):
https://www.youtube.com/channel/UClRwC5Vc8HrB6vGx6Ti-lhA
You can support this channel on Patreon! It has been amazing what Patreon has done for this channel, but also for me (your dorky host) personally. Through the support of people just like you, Technology Connections has become my job and I am so excited and thankful for it! If you’d like to join the fine folks in a pledge to help the channel stay as weird as it is (and maybe, just maybe, get even weirder!), please check out my Patreon page. Thank you for your consideration!
https://www.patreon.com/technologyconnections
And thank you to the following Patrons!
Viorel, Reaghan Kekeis, lohphat, Vivian Pypher, Brandon Whiting, Scott Herron, Zachary Hazlett, Peter Stewart, Patrick Barry, Robin Johnsen, Nomad, Eric, Phia Westfall, Jeremey Hastings, Mark Wayt, Matthew Reynolds, Dave Howlett, Arthur Robillard, Sonic the Anonymous Hedgehog, Lee Tustain, Ramon Gamez, Marcel de Jong, Vaughn B., Breunie Ploeg, Braden McDorman, Stephen Bank, Julien Oster, Jake Hickman, Trae Palmer, Gary Hampson, Lennart Rosam, Chris Wallace, Matt Shea, Jason Baker, Galimaufry, PJ Gunasekera, Adisibio, Aaron Helton, Michael Holmes, John Piontkowski, Trey Harris, Peter Pfundstein, Wilhelm Screamer, Mat Stu, Charlycobra, Thomas Kolanus, William Kisley, Daniel Johnson, Potch, Reemt Rühmkorf, Jack Nichol, Robin Rattay, Bruce Justyn, Rae McIntosh, Justin D, Adam Zawisza, LordJakson, Triancia, Max Barnash, Microfrost, Sinirlan, Mitch Schenk, Juan Olivares, Mike Bird, Emmett Ray, Michael Shaffer, Sputnik, Jason Spriggs, Danny S., Gregory Kumpula, Chris Zaremba, Tom Burns, Daniel Pf, Yung Kim, John W Campbell, Matthew Jones, Dave Redmond, Slappy826, Steven Ingles, Robert Howcroft, Troy King, Some Random, Jeremy Heiden, Vince Batchelor, Peter Sarossy, Tracy Cogsdill, Matt Allaire, Guy, Benjamin Gott, Luke, Zach Le, Fredrik Østrem, Anil Dash, Simon Safar, Michael Wileczka, John Ehler, William Matthews, Fred Leckie, Julian Zielke, John Rogers, Kenneth Morenz, Andy, Adam Merolli, Greg Stearns, Zack, Robert L LaBelle, Chris Satterfield (Compgeke), Cameron Benton, Samuli Suomi, Keith McCready, Jeffrey Glover, John Marshall, Hsin-Kuei Chen, HenryD, Damian, David Anez, Josiah Keller, M T Bono, Conall Ó Maitiú, Struan Clark, Keeb, Tarrien, Jason Viterna, DrMoebyus, Biking With Panda, Chris Larsen, JH, Michael Romero, Jonathon Mah, Jonathan Polirer, Derek Nickel, Marc Versailles, Ian Pirner, Mark Stone, Arthur Zalevsky, John Fruetel, Christopher Swenson, Andrew Diamond, Cole Campbell, Christopher Beattie, Paul Bryan, Samuel Kirzner, Gus Polly, Daniel Pritchard, Brandon Tomlinson, Eric Loewenthal, Jeremy Samuels, Malcolm Miles, Matthew Lloyd, David L Jones, Matthew Burket, Mike Burns, Noah Corwin, Andrew Roland, Luke Whiting, John Cockerill, Smith8154, David Groover, Michael Wehner, Kyle Creasey, Rainbow Warrior, jacob kamphaus, Slysdexia, Alex Hurley, D.z, Andrew Bobulsky, Matthew R, Richard Sams, Andy Kettu, On Ice Perspectives, Brian Wright, TheGreatCO, Marcus, Ethan R, Petteri Hjort, Daniel DeLage, Nathan Obuchowski, Sam Tran, Shaun Puzon, Bret Holmes, Vlycop, Alexandra Stanovska, Tom Ebenhoe, Casey Blackburn, Matthew Jensen, Devon Hodgson, Paul Macejewski, Case Tu'ikolovatu, Zimpan, Loïc Esch, Filmmaker IQ, Jan Houben, Bren Ehnebuske, T.J. Zientek, AdamPlays, Vernon, Ton Brands, Scott Wright, Jason Ashcroft, Kory Howard, William Lahti, Thanasis Dimas, Marc Grondin, Lisa, Hex, Mark Stradling, Gareth Lucas, Anton Mironov, Peter Sodke, joseph, Kristian Scheibe, Jacob B, McLargehuge 510, Andrew, Nick, Greg Tan, The Masterpiece, Seanvdv, Chris Cody, Chad Fertig, M Shrimptoast, Joseph Houghtaling, Ben Tucci, Seph P, Dave Stares, Josh Braun, Lachy Bell, Joe Johnson, Daniel Dugger, Christopher Lowell, Oleg, Michael Sacchi, PC Perspective, Allan Parker, Ali Elam, Dan Allen, Trent Crawford, Zhenbang Xiao, Maxime Aubaret, Markus Towara, Barky doggo, Ectra, Dylan Taylor, Reid Fishler, Emmanuel Jaramillo, Daniel Meagher, Joel, Neil Richardson, Clemens, Brian Kerber, Miranda Schwarck, Bill Bates, Centronias, Dennis Walsh, Nuno Silva, Alex Warren, marc lulkin, Christopher Moyer, Christian Schulz
Don't ya love it when you’re learning
about something and things, just, click? Like a light switch! Clicky switches are pretty fun. But why do switches make noise? What’s the point of all that clacking? Well, it has to do with the fact that you’ve
been lied to. Uhh, but let’s not get too conspiratorial
just yet, first let’s look at some of the switches that don’t click because there
are some. This electronically controlled dimming module
turns the lights on completely silently. No clicking there
. Then again, this other one that’s not a
dimmer makes a pronounced clicking sound. [pronounced clicking sound ] And I didn’t even touch it! What gives? Well, the dimming module is using a solid-state
device known as a triac to actually turn the lights on and off, so it’s not quite what
I mean by a switch. This standard thing goes on or off module
does in fact use a type of real switch to do its work, so you hear a click. [click] Same with this toggle light switch. [click] This rocker switch. [c
lick] This rotary switch. [click] This lamp cord switch. [click] This power button. [softer, double click] The rocker switches
on this studio light. [four clicks in a row] Oh, and the big one,
too. [a somewhat softer click] This toaster. [a click that’s Automatic Beyond Belief] The mode selector on this space heater. [clicking as it turns] Even its thermostat
makes a distinct click. [soft, repetitive click] But why? Why be so clicky clacky all the time? To start to answer this question, we first
need to answer a simpler question; what is a switch? Well, a switch is a handheld game - no. A switch is a mechanism used to divert rail
cars fr - no. A switch is the simplest mechanism that can
control the flow of electricity. [pleasant chime] Say you have a simple table
lamp and want to connect it up with the power grid. Well, we simply take its bare wires and carefully
touch them to these live wires and voila! Let there be light. Now to turn the light off, all we need to
do is carefully pull
those wires apart, and hope the live ones don’t t-- [electric arc
and explosion] But this is pretty dangerous. Even Edison knew that. So we designed electrical sockets which contained
live wires behind an insulating barrier and we designed plugs that would, depending on
your country, somewhere between somewhat safely and completely safely allow you to make and
break electrical connections. But this isn’t the most convenient way to
turn something on or off. And most importantly, using them that
way
isn’t good for your plug or your receptacle. See, if I take this lamps and plug it into this outlet, it lights up no problem! And if I simply unplug it, it goes out, also
without a problem. But watch what happens if I take this space
heater and unplug it while it's running. Ooh, that was quite a spark! Let’s do it again! Ooh! Let’s do it again. Ooh! Big one! Let’s do that again! Ha, Let’s do… let’s do that again! [VOICEOVER]: While this specimen continues
to be amused by the sparks, we’ll mo
ve on to the next jump cut. (ooh!) When the heater is running, a lot of electricity
is flowing into it through this cord. 1,500 watts, in fact. To stop that flow of current, all we need
to do is put an insulator between the contacts of the receptacle and the pins of the
plug. Which of course we can do simply by unplugging
it. But when we unplug it, it doesn’t just stop
the current flow right away. There’s a brief moment where that current
manages to jump out from the outlet, and the result is a
spark. The same thing happens if you plug in the
heater with it turned on, right before the pins of the plug and the receptacle first
make contact, but the spark usually isn’t as large as when an active connection is broken. And this is where you’ve been lied to. See, when you were little, you were probably
taught about electrical conductors, like the wires in this cord, and electrical insulators,
like the plastic insulation surrounding that wire. If you had a really nerdy teacher you might
have
learned about semiconductors, but lots of us were sorting things into the two categories
of insulators and conductors. The lie is that, just like most things in
the real world, the electrical conductivity of any given substance exists on a spectrum. Everything conducts electricity when you try
hard enough. Even air. Now we rely on the resistance of air all the
time! Electrical transmission lines are typically bare aluminum
and are held up in the air by stacks of insulating discs. The higher the
voltage of the line the more
of these discs you need because even they aren’t perfect insulators. Nothing’s a perfect insulator! And that’s the problem. Air’s pretty good, and when you unplug something
from an electrical outlet you do disconnect it from the power grid and stop the flow of
electricity to it precisely because there’s air now between the pins of the plug and the
conductors in the receptacle. But, when you pull that plug out of the wall,
there will be a brief moment when there’s on
ly a tiny bit of air between the plug and
the socket, and this is not good. When those contacts are close but not quite
touching, the air gap is so small that the breakdown voltage, that’s the voltage at
which an insulator fails to stay an insulator, is lower than the voltage of the electrical
supply. This means that the current will actually
jump the gap, and this creates an arc discharge. That’s the spark you see here. Now on its own this isn’t particularly bad. Thanks to the fact that we use
AC power, the
voltage crosses the zero point 100 or 120 times per second, so that arc will usually
go out nearly immediately, though it should be noted that arcs can be sustained on AC
power. More importantly, the breakdown voltage of
any insulator, including air, is a function of how thick it is, so once the contacts are
just a millimeter apart, that arc will generally be unsustainable. But here’s the problem. That arc is hot. Very, very hot. So hot, in fact, that it can burn the ends
of the pl
ug and the socket. So we don’t want to rely on pulling the
plug out of the socket to stop current flow. What do we do instead? We use a switch. All the switch does is create a break in a
circuit. There are many different types of switches
but they all do fundamentally the same thing. There are two electrical contacts, and they’re
either touching, or they’re not. If they touch, current can flow. And if they don’t touch, current can’t. But then, switches do the same thing as unplugging
it! Don’t t
hey have to worry about arcing? Yes, in fact even more so. Electrical arcs damage electrical contacts
in various ways, but among the most significant ones is that the contacts eventually… melt
away. See, each time there’s an arc, that plasma
is so hot that the surface of the contact briefly melts, and that material can sputter
off of it. Additionally, the high temperature can cause
corrosion of the contacts, and you get lovely issues like carbon buildup which increases
the electrical resistance
of the contacts, and that’s not good. Even better, if the arcing is bad enough,
and the surface of the contacts get hot enough, they can weld together and get stuck closed! I guess that light’s on forever now... Since the contacts in a switch are generally
pretty small, we want to minimize the arcing that can happen because, well, an arc will
warm them up quickly and cause all those problems I was just going on about. And how do we do that? Why, with speed! Remember that household voltages are l
ow enough
that an arc generally can’t be sustained once the contacts are just a millimeter apart. So, if you get them apart quite quickly, any
arc formation that does occur will be very brief and unlikely to cause significant damage. And that is why switches click. [click] Switches are designed with mechanisms
to ensure the contacts open and close very quickly, quickly enough to prevent an arc
from lasting more than maybe a millisecond or so. Effectively the contacts are meant to slam
together a
nd then get yanked apart, and that makes an audible click. The mechanisms that accomplish this are often
ingeniously simple. Many times it’s just a spring cleverly integrated
into a pivot. Let’s take a look at a simple household
rocker switch. This switch is nice and clicky. [repetitive, rapid clicking] Who needs a fidget clicker
when you can just run to the hardware store and get one of these? This design is almost devilishly simple. Below the faceplate are three pieces of brass,
two of which a
re the same ones you attach wires to on the outside. The smaller one holds an electrical contact,
and the larger one serves as a pivot point for a small swinging piece that holds the
other contact. If there’s a torque applied to the swinging
piece in this direction, the contact does not touch the other one, and no current can
flow through the switch. But, apply a torque in the other direction,
and now the contacts touch. Current flows into the switch through this
terminal, through the basket thi
ng, into the swinging thing, through the two contacts,
and out the other terminal. All it takes to ensure the swinging contact
moves quickly is a spring. See, the rocker paddle that you touch is in
fact the same thing moving the contact. These grooves hold onto the edge with a little
play, and when the rocker rocks back and forth, so does the contact below. But thanks to the spring, the rocker (and
more importantly the contact) wants to stay in either position. The spring gets increasingly compr
essed as
the rocker meets the apex, and once it passes it... [click] bam, the spring expands and pushes the
contact it in the other direction. The result is a swift action in both directions,
minimizing arcing. Pretty clever. Unfortunately, though, this switch design
isn’t perfect. In fact, many (if not most) switches on sale
today aren’t. See, you can actually move the contact a bit
before the spring takes over. If you carefully apply pressure on the switch,
you’ll see that the light goes out b
efore it clicks into the off position. Listen carefully and you can actually hear
arcing going on inside the switch. [faint arcing sound] This… isn’t really
great, especially if you have a lot of lights on the circuit you’re controlling. In fact you can see on these contacts that
they have been slightly damaged, and this isn’t a very old switch. I know because I installed it myself. Granted, most people don’t turn the lights
on and off like this. If you do it like a normal person, then the
conta
cts are swiftly moved and arcing is minimal. Still, it annoys me that it’s even possible
to damage the switch at all. Many switch designs, like these lamp cord
switches, are simply impossible to hold in a half-on, half-off state. Sure, they’re not designed to carry the
current of a normal light switch, but I bet these guys rarely ever fail from bad contacts. And normal switches can be made impossible
to abuse. The house I grew up in was quite old, and
a few rooms had toggle light switches that y
ou could actually move nearly completely
into the opposite position before the internal mechanism opened or closed the contacts with
a very loud clack. [a very loud clack] Those switches were in
service for 50 or 60 years and likely still are. Granted, they were only controlling a single
light in all but one case (if memory serves) so they weren’t ever under much electrical
stress, and they required much more force to use than modern switches, which is probably
why that style went out of favor.
But, this paddle-style dimmer switch has a
mechanism that prevents partial making and breaking of the contacts without requiring
significant force. You can see that even if I use my two thumbs
on both sides of the switch and very, very slowly move the paddle, the lights only go
on and off with the click of the internal mechanism. This design here is what I’d call ideal,
and it proves that easy-to-use switches can still be made with a fast, clicky, abuse-proof
mechanism. So if you’re shopping for
a light switch
at a hardware store, tactile feel of the switch does actually matter when it comes to switch
longevity. A nice, solid snap makes me more confident
than a smooth, quiet movement. This cheap toggle switch is what I’d consider
awful. The toggle moves smoothly without much resistance
at all, and the contact is actually broken when the switch has barely moved out of its
resting position. It actually requires conscious effort to ensure
the contacts are quickly moved apart, and I doubt
this switch would last more than a
decade on a circuit with more than a few lights. In fact, it’s not even fair to say that
this switch actually clicks. It more or less thuds. Any switch that’s designed to interrupt
even a modest current flow should, in my opinion, have a nice audible click. That plug-in thing-goes-on module? It got a relay in it. Relays are electromechanical devices that
control large currents with small currents. Essentially they’re a switch with some sort
of external control.
In this case, the small computer inside here
will turn on the relay when it’s been asked to, and click, the light goes on. The contacts in a relay are closed via an
electromagnet, and are held open with a spring. And, as luck would have it, this simple arrangement
means the switch opens and closes quickly. And so, it clicks. Fun fact! When we need to automatically control very
high current loads, we use what are essentially large relays, but we call them contactors. Contactors often just use ai
r to break the
circuit like any other switch, but when we get into high voltage applications, the contactor
might be contained in a vacuum, and in really high voltage applications like in power grid
substations, you might find switches and circuit breakers inside a volume of sulfur hexafluoride,
which is an incredibly good insulator and this is in fact the primary commercial use
of SF6. Now, not all switches need to click. Switches that don’t carry a lot of current,
like the clicky buttons on yo
ur mouse, don’t need to click at all because there’s not
gonna be any arcing going on in there. They click mainly because that style of switch
is designed to provide a lot of tactile feedback. And actually, a very clicky switch can be
a disadvantage in digital devices, because now you might need to implement some sort
of debouncing but that’s beyond the scope of this video. So. Now you know why switches click. They’re really just prolonging their life. And if you want to prolong the life of the
switches in your life even more, be sure you always give them a good flick. Or, poke. Since many modern designs kinda make you a
part of the contact closing and opening action, you can and should click to your heart’s
content. Thanks for watching! And thank you to the fine folks supporting
this channel through Patreon. I really do appreciate your support. If you’re interested in joining these people
in supporting the channel, you can check out the link at the end screen, or in the
description. T
hanks for your consideration, and I’ll
see you next time! ♫ illuminatingly smooth jazz ♫ Nope. I messed up. I thought this would go quickly, it’s not
going quickly. So, if you get them apart quickly … [clears
throat] That was going well, but then it wasn’t. Wrong pronunciation! [struggling sounds] No no no, that’s the wrong way! [more struggling sounds] [also the tripod is creaking, that’s fun] Now, no I don’t like how I did that eith… eugh. eugh, well, ugh. Cra.. that might have been, erm, neve
Comments
"Everything conducts electricity if you try hard enough" as an electrician, can confirm LMAO
did... did he get through all that without saying "click subscribe"? my man
As a UK resident, I love how US plug sockets look eternally surprised.
Nice click sound is also good positive feedback. The positive feedback is very important in the human design. It makes things intuitive and giving you info "you doing it right"
When I was young I used to try get the very old switches to sit in the exact middle. I now understand why I caused so much damage and got in so much trouble.
Switches: exist Humans: balance the switches in the middle so the light starts flickering. Switches: bruh
I honestly laughed my ass off at the constant "OoooO lets do that again!" while pulling the plug out of the wall. You have a great way of satirically promoting safety because I can totally see children literally playing with that.
I can't get enough of your subtle humor. "Professional driver" got me giggling good
Awwww, you didn't mention turn signals! The "click, clack" of turn signals used to be caused by the relay that controls the bulbs toggling on and off. Now cars use solid state relays, so the clicking sound is produced artificially by a speaker under the dash.
I flicked the switch as hard as I can, but the joycons still drift.
1:56 - When Technology Connections and Electroboom have a crossover episode.
As an electrician, i really like it when you explain basic everyday stuff using explanation with knowledge in reasonable order. Keep up the good work!
The fact that a video like this exists makes me love this channel even more
The tiny arcing is the reason why you should never turn a light on if you smell gas in a building. Excellent video as per usual.
Just behind the house where I grew up (about a mile from a power plant), there are a series of high tension towers, with dozens of power lines heading out over the region. We used to stand beneath them with fluorescent tubes and play light saber, because they would light up as you held them. Don't know why this memory came to mind, but these videos always make me think.
When I was a kid some houses had silent switches that had a vial containing a small quantity of mercury. Two metal contacts were at one end of the vial. When the switch was off, the vial was tilted so that the mercury was at the far end. When it was on, the vial was tilted the other way, and the mercury would complete the connection between the two contacts.
"Let's do that again" -Famous last words
"Let's do it again!" Label: "WARNING: TO REDUCE THE RISK OF FIRE"
At 3:05 an awesome line would have been "if this grown man is this amused by this, imagine how amused a child might be"
Oh... I'M SO SHOWING THIS EPISODE TO MY GRADE 9 SCIENCE STUDENTS. This was one of the most clever episodes I have seen in a long time. The arc images that you captured were particularly interesting. Well done, sir.