PWM (Pulse Width Modulation) as Fast As Possible
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- Опубліковано 2 лют 2017
- PWM is a technology that enables cool things like RGB lighting and variable-speed fans. How does it work?
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How does my computer put on a fantastic light show? It doesn't.
@@MrLukzor PC hobbyists have never been creatures of necessity. If that's all we cared about everything would still be beige. Most of what pc modders/enthusiasts (aka Linus' audience) do isn't "needed." Is a 5ghz overclock "needed?" No, if you "need" that much power for work, you would have a multi-CPU workstation or something. Is a custom water loop "needed?" Nope, they take way more work, are super expensive, and don't work much better than air cooling. Some things you do just because you can, or because the rule of cool dictates.
Not to mention some RBG _is_ useful. Keyboard back-lighting is nice to have at night. People always want color choices, which is why RGB exists in the first place. Case lighting is also useful for being able to see that everything is as it should be, not getting too dusty, etc.
You can also make things change color according to different temp sensors, so you see how hot things are running without having an overlay on the screen. Sometimes I have the numpad and arrow keys showing CPU and GPU temp while playing a game.
But again, who gives a shit if it's necessary? I like being able to change the colors of everything and make schemes for different games with keybinds/macros highlighted. I'm about to get a few strips for screen-responsive bias lighting on the back of my monitors and build a custom RGB infinity mirror inside my case. Nobody "needs" an infinity mirror, but they look cool as hell and they're simple to make. It's funny how all of a sudden it's cool to hate on RGB, but somehow it still sells like crazy. The people who pretend to hate it are probably the ones who have never built a PC and are using a 10 year old Dell.
But yeah, congratulations on being an RGB hater... Enjoy your bland PC experience, I guess?
@@MrLukzor r/woooosh
(the whole point of my comment was that it doesn't need to have any purpose other than cosmetic)
@@MrLukzor Yeah omg I typed more than 2 sentences, must have taken forever.
@@MrLukzor Yeah I forgot kids these days are only capable of reading 140 characters at a time.
Some of us think in essays rather than tweets. Some of us also type fast, so getting those thoughts out is trivial.
Here's another thought for you: I haven't had "free time" since I was a teenager. What I have now is "earned time" and "earn _ing_ time." Sometimes they bleed together so I use some earned time to explore more ways of earning. The beauty of being a self-employed grown up is nobody tells me how to use either of them.
So if by "free time" you're referring to "earned time," yeah I have a decent amount. And that's what most people ultimately want, so... yeah sick burn.
@@MrLukzor lol of course when someone makes you look dumb they must be "mad."
Did those pixies have Linus faces?
Me too
DTM1218 you guys are freaks but funny
DTM1218 you guys are freaks but funny
What is seen cannot be unseen!
Yes. since luke searched about "linus".
Within 2 hours of using my first LED backlit monitor I was having eye strain and a dull headache. So I researched, learnt what PWM was, refunded that monitor, got one without PWM, and, haven't had issues since.
The old monitor I had probably used PWM as well, but it was CCFL backlit. CCFLs have a slight glow after flickering off, so the negative effects aren't as severe as LEDs that are immediately dark when off, it's the harsh bright light to zero light of LED flickering which fucks some people up.
hey man, i havea benq 1080p for 5 years now but bought an lg 4k monitor recently and its hurting my eyes immediately. Like within 10 minutes my eyes becomes fully red and the bloodveins are all over my eyeball. I thought my vision was worsening but then i tried setting up my benq again to see if it wasnt just the monitor and i swear my benq doesnt give me this issue. Im researching just now what the issue is im suspecting it is indeed this thing called pwm.
PWM is not the problem par se, its the slower speed PWM frequency, as it approximates the reaction time of the eye (20Hz) it can cause eye strain.
@@suzesiviter6083 This is correct. Old cold cathode (CCFL) backlights had a very low PWM frequency, and frequencies lower than 30 have been proven to cause headaches in some people and seizures in epileptic people. However, not everyone is effected by this.
PWM is also used in old game consoles to give you that nice 8-bit sound.
EDIT: sorry, this isn't actually true. Check the conversation below for the actual truth.
Meta - uhm - not really.
the 8bit guy made a good video about how consoles made sounds.
ABaumstumpf oh, i have actually seen that video...
The reason i made that comment was because i a digital synthesizer (called Massive) that allows you to make sound using PWM. And it sounds really 8-bit.
NI's Massive uses regular wave form oscilators... 8bit sounds comes from square waves.
Eduardo Walcacer yes, but the PWM Wavetable generates more that a normal square wave, it changes the pulse width (surprise, surprise...) of the wave, which sounds different.
Every old 8bit tune was made using square wave synthesizers and nothing you say will change that. PMW only allows you to use any waveform (even images) as oscilators.
L: Linus'
E: Equipment (is)
D: Dangerous
R: R.I.P
G: Gorgius
B: Builders
L: Linus
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D: D1K
Thank you, i've been looking everywhere for a simple explanation of PWM
I agree and this helped me understand what I can use this setting in motherboard for.
PWM is also a technique used in music synths. The pulse oscillator's pulse width (duty cycle) is modulated by a low frequency oscillator (LFO).
A flicker rate at or below 30 hz is KNOWN to be a cause of headaches and seizures. It isn't marketing, even if the issue only affects those sensitive to it.
Umm you know that's a feature right?! & NOT having it isn't something good it's not the same as missing a headphone jack it's like losing a feature
@@rayanhuss5952 How is having a flicker slower than 30 times per second a 'feature' in lighting? I guess causing all the epileptic people to have a seizure could be seen as a 'feature' for some people...
@@rich1051414 Right? I know several people who are stuck on their old iPhones or have been forced to downgrade from their XR/11 to get an SE just cause they’re sensitive to pwm and can’t use oled phones. That’s so sucky for those people I wish they’d just let you turn it off
Exactly!
Great video Luke! Always enjoy learning something new
I'd only heard PWM when talking about case fans... You learn something every day!
Thanks for putting this out, so many people I've talked to about this subject just assume dimming LED's was just as easy as using pot (which is possible) but usually ends up with a burned out LED.
It was the first time I watched your sponsor message in the video. Good Job on keeping the tone the same :-)
pwm is also used for communication between RC radio controllers between the motherboard and the actual radio module. all ~16 control channels/signals can travel through one wire
That was very beginner friendly and well explained! Thank you, Sir!
Thanks for the explanation. I greatly appreciate how you simplified it. I was having a hard time comprehending the concept.
Flicker at 60hz is painful.
30hz on an old TV is acceptable because the old style phosphors used to light up the screen had enough image retention that you generally didn't see the screen go blank.
High end PC CRT's with low image retention (better for high FPS) would emit light for just a small duration of the 16ms frame time at 60hz, and in my entire life I have NEVER used a CRT at below 80hz (willingly).
I'm betting that if you were to use a very short burst of light, lets say 1ms, it would still be noticeable even at 120hz.
Can you explain about Onepkus 7 pro PWM frequency ? It will be very helpful.
Thanks.
Love your smooth subtle trsnsition between the pertinent stuff anf the sponsored stuff.
*doodie cycle*
Those Linus pixies have scarred me for life...
bruh i fapped
Damned I don't care if Linus is a big fan of RGB lights.
flickerinug monitors melt my brain
PWM is also used with servos in RC planes, rc cars, and rc helicopters control the position of the servo output shaft or arm.
Christ, that transition into the ad-spot was seamless!
PWM is also used on trains built between the 70's and the 90's, that causes the typical buzzing sound trains from that era does. In the 90's train manufacturers stopped using PWM for new AC VF systems that were more powerful
PWM in a dim light situation causes eye strain. you can actually see the flicker if you gave a screen a good shake
Another automotive application of PWM is in the Engine Control System; it is how the fuel injectors are controlled for optimum fuel atomization in the combustion chamber, which reduce emissions and increases fuel efficiency.
sometimes i feel like these guys read my mind and upload content accordingly its amazing :D whats in the box video with the 7700k and the 600p guess what 1 day earlier i bought the 7700k and was considering the 600p... now i was considering to buy the pg248q monitor guess what yesterday they upload pg258q and i wanted to know more about PWM a couple of days ago and they upload this video :D you guys are awesome.
It really does make a difference in monitors. Old CRT had a very low pwm frequency and new have a lot higher, and they feel a lot better. Also there is an app that tries to remove pwm from the monitors completely - Iris.
0:12
brb, filling my case with pixies and dimmers.
Good info, straight to the point. Well done.
The old time dimmer switch explanation is brought it home for me
PWM lit backlights at a small enough brightness level do start to flicker clearly, there are ways around it of course, but on the cheaper monitors it's not used. In fact, you can decrease the blur on an lcd by having the pwm cycle synced to refresh rate, that means the screen is flickering, that means it can cause eye strain.
attach a capacitor in parallel with the led's to smooth?
18Hz. Flicker fusion rate. Yes for evenly lit frames. Not for light. A 24FPS cinema runs at 48HZ, each frame are shown twice.
You can test this yourelfs with a a camera flash. The flash must have a "multi flash" setting ware it acts as a strobe. On mine I can set the number of flashes and the Hz. To my eyes the light output becomes solid around 50-60Hz, and continues to be smoother up to 100Hz witch are max on my model. At 20Hz it are still obvious it are individual flashes.
I'm sure someone at LTT have a flash that can do this. So test it out for yourself!
your explanation style is super and add some more information
Phone audio is P"C"M not PWM. Pulse-code modulation. This is usually 64kbit/s and is further encoded using hybrid encoding which sends small fragments of the actual audio and then a series of synthetic parameters to modify the sound into the original. So it's a mixture of PCM loss less, 64kbit/s chunks and the rest is vo-coded by a synth. This is why during very heavy network usage, like at a concert or at new years and you phone a friend they sound like a robot. Because there isn't enough bandwidth to send much of the PCM audio and the majority of the signal is low bandwidth "vocoder" style voice. "Vocoding", originally invented by the military only sends basic synthetic filters and functions to recreate the voice. Rather than sending the high quality audio, they just send synth settings to reproduce it, this requires minimal bandwidth. Phones hybrid this with the PCM, the more bandwidth available the more PCM.
PWM is just a way to convert analog signal waves to digital by varying the length of the digital 1s and 0s to match the analog wave. Described as fast as possible.
So many misconceptions.
Pwm does not change the perceived power, but the actual power. If you go with 100% power but only 10% of the time, than the end result is 10% power.
The power-consumption of PWM fans too is not choppy.
The PWM signal is NOT delivering the power, it is only telling the inside circuitry what to do. And there is a surprising amount of electronics inside those fans.
With current regulated fans the extra power can get wasted, but that is not the only way to do it.
And light-dimmers did NOT work that way either - or they would have burned up.
Some early versions used a transformator, but pretty much every conventional dimmer uses triacs since the 19070's.
phones and celltowers do NOT use PWM to transmit data. that would be rather inefficient.
GSM uses Minimum-shift keying.
PWM amplifier - you mean class D amplifiers?
Cause they can use PWM, but are not limited to.
not a bad video, but surprisingly nearly everything is only half true or outright false.
ABaumstumpf I believe it's for noobs on low-level electronics, those that mix concepts like power with voltage. It's better than nothing I suppose
I was waiting for a mention of class D amps too. Especially in live sound loudspeakers, line array systems, etc.
ABaumstumpf yeah as a EE student this video had me cracking up. They should stick to unboxings, they're clearly not qualified to try and educate on topics like this.
In first line you put 5 instead of %
And you're right
Karol - oh, thanks, edited it.
as an electronic music artist, pwm makes me very happy!
A very good explanation. I was wondering about how to set this on a board and now I know what to do. Thank you Luke and I am your father. LOL
PWM is also used for LED car headlights and taillights to control brightness and temps, which is why they flicker in some videos.
Good video I watched it all the way through
10/10 best transition to sponsor ad ever
Dude this channel should win an award
Requested this! Very nice
Yesterday i bought a Arduino UNO Thank you!
about tunnelBear - that's aweosome!
I can't believe I'm watching this to get ready for my college project final presentation
iphone x gives me headaches. I tried to film it w a different phone in slow mo and the white continuously flickers.
Did not know about PWM until today because I just got a new laptop & my eyes where tingling after a while & that night i had a really vivid dream. I will have to cut back kneeling before my neon god before bedtime.😵
Thank you for the explanation. But, do I need a program to make PWM work correctly? Or is it plug and play like the fans that don't use it?
I thought PWM stands for Pixie Wave Management
I feel like the tunnelbear spot at the end was transitioned to VERY abruptly, it basically sounded like your previous sentence hadn't even finished yet.
Thanks for explanation.
Ugh THANK YOU FOR THIS VID!
I actually CAN see PWM that flashes faster than 18 times for second.
Whenever I look to the left and right of those LEDs, the motion blur appears choppy. While I can't tell the difference looking directly at it, it looks annoying when I look from side to side in a PC. I would rather have less efficient LED string that's always on, then on that looks flickery.
The Doodi(Duty) Cycle! I love it!
in some situations PWM is used across a capacitor to perform DCVC safely and more efficiently.
Cool stuff.
So essentially:
PWM = More efficient, more cool, and less power consumption
Great!
Personal Experience: I had updated my BIOS and for some reason my idle temps shot to 45-50C when it was a nice 29-33C before...understandably I was scrambling to find out WHY this was, for almost 2 days I tried everything I could, hell almost reverted back to the old BIOS version, and then finally, tonight really (8/31/2019 to you in the future) my brain would NOT let this go and so I went into my BIOS and I was messing with the fan controls and I pressed PWM and INSTANTLY my temps shot back down to their original temps and I sat there and I was like...no way is it that easy, I bet it's gonna up any second now....NOPE stayed true to the 29-33C range! :D so yes PWM is an amazing thing and I'm so glad I was finally able to get my temps back to what they were originally
Side Bonus: Before I discovered PWM my fan was pretty loud but now its super quiet as it was before! (I use a AIO Liquid cooler just btw)
Very useful feature !
PWM stands for Pixie With Magic
It was mostly accurate until you started taking about audio amplifiers, at which point you tried to equate class-AB vs class-D amplifiers with DC vs PWM. this is not correct or even vaguely accurate for reasons too long to type on my phone, but basically, both amplifier classes receive and produce smooth AC audio. the internal function of a class-D amp involves a varying duty cycle as a product of a sine wave and triangle reference wave, but that's as related as the two topics ever get
IamIronManUK Didn’t fully understood..but got it.Tnx
It's also what gave the C64 its distinct sound.
Never thought that a LTT video would help me in my Aerospace LAB class...
realy good video
PWM does give me headaches.
Had no idea this channel was over 5 years old.
It took me a second to figure out, but I think you may have left a question unanswered (or maybe your wording wasn't clear).
You may have talked about it in your RGB video but the PWM pulses will pulse each individual diode depending on the data value that was given to it. This will vary the brightness of each diode allowing the combination of colors to occur. For example, an RGB value (vector) of 0,0,255 would tell the controller to give 0% PWM to Red, 0% PWM to Green, and 100% to blue producing a fully lit, blue light whereas 128,0,128 would produce a half as bright purple color.
Been a while since I've messed with LEDs, need to get back to microcontrollin'
Nice representation bro ,
OMG I LOVE THAT GAME THEY ARE DOING ON CHANNEL SUPER FUN ITS AWESOME
also, PWM dimming on car tail lights pisses me off because when I move my eyes it gives me stroboscopic effect, you can also explain this.
comes from some people being too cheap for the extra 0.2 cents for the faster switching PWM-chip.
You mean from manufactures being cheap, right? Most newer cars come off the line with LED bulbs for the rear end.
+ABaumstumpf PWM are themselves cheap as fuck alternative for corporations instead of having an actual proper dimming circuit. You can see this in how monitor companies are now marketing these "new and improved eyecare flickerless" monitors, i.e. non-PWM brightness circuit. In other words: they're now doing what they were MEANT to do from the very beginning. They're cheap motherfuckers. PWM should have NEVER reached this level of popularity for light management.
+m8onethousand PWM with LED lighting actually serves a good purpose if done right... I agree it shouldn't be used to control brightness, a good pot is better for that, but, PWM when used properly can help increase the lifespan of the LED, as well as decrease overall heat output since it's not lit as long.
m8onethousand - PAM light dimming actually is quite good.
But the the frequencies need to be higher in order to not have any problems - and that is where they cheaped out cause ti would cost half a cent extra.
With LED backlight it is possible to dim them directly, but with other backlights - CCFL can not be dimmed all that much as the physics they are based upon limit the range significantly.
Increase the PWM frequency and you got no problems.
some panels have frequencies as low as 125 Hz - and that is too low. with just a few cents extra you could pump that up to > 2000 Hz and have no flicker what so ever.
You should do a video about Pulse Code Modulation next, show how that works to make music.
PWM with LED backlights on TVs/Monitors is absolutely horrible. Talk about extremely painful to look at. I get headaches, fever chills, nausea and I even loose my sense of balance a little. I have to use a really outdated Dell E173FP monitor for my computer because it uses a CCFL backlight and doesn't cause me such horrible eye strain.
give pcmonitors.info a look, he only features monitors without it
The perceived brightness doesn't work linearly but logarithmically, so at 25% it'll be at half brightness and the difference between 1 and 2% DC could be about equal to the difference between 70 and 85%, blame your eyeballs for that :p. It's similar with sound too AFAIK.
wonderful
How fluorescent lamps work and their types
PWM is also used in modern Automobiles. Such as an EVAP Solenoid.
Also you need an oscilloscope(PICO SCOPE) to work on most things that are controlled by PWM.
So is this kind of like Morse code for power? Is it always a constant, or is it patterned for certain things?
I find it's very easy to cross the line from pretty color-coordinated PC that showcases the components to tacky strip-club in a box
Does anyone know if this can be used or adapted somehow to control speed/power-efficiency in a hand-held drill? Or how I could adapt circuitry for a safety shutoff?
I am a fan of these hobbyist electronics fast as possibles.
Can you make a video about pwm vs smart fan mode.. very interesting topic..
I don't think dimmer switches were ever resistive. The DIAC/TRIAC has been around a long, long time.
And... PWM does NOT drive PWM fans. Not like PWM leds are driven directly from the PWM. In the fan the PWM is just a control signal for the controller in the fan. The fan itself is run off a multiphase brushless setup or standard DC commutators. There is no load on the PWM, it's pulled high by the fan and the motherboard just connects it to ground (the invert of the PWM signal).
Like many bothered by PWM I only discovered it because I found certain displays horrible to look at, like the iPhone X. It was hard to even focus on the screen. I feel like they've improved the iPhone oleds to combat this...
can any Dc motor is controlled by using PWM technique or there wiil be separate motors for that pwm control???
Ok, i have a question. I am doing a pc build and my motherboard, the maximus ix hero has 4 fan headers. Im wanting to hook up 6 fans, the corsair ml140 fans. I dont want to use a fan controller or hub, but is it possible to use a fan splitter and not mess my motherboard up? Ive heard you can do this, but i also heard its dangerous. Please help me!! This is the only thing slowing me down on this build.
Omg Linus faces on the pixies!!
PWM absolutely does cause eye strain for some people on PC monitors. I’m one of them. :(
RGB LED!
Can you please make a new video on this with new devices! Everyone needs to know
Thanks for this video. I suspect the MOBO I'm looking at uses this for RGB which... I"m uninterested in.
pwm I see you learn new things everyday I guess
1:35 proof that you cant see over 18fps
Is this a joke or are you fucking dumb
if you can't tell it's a joke, maybe you're the one that's fucking dumb.
Dan Super wasn't funny bro..
I meant the horseguy*
Wait what?
Hope that you guys can tell something about diskless workstation
Uuhmm, I also have eyestrain from some PWM monitors. Up until the point I can't look at any screen for a while anymore. It's no joke. Especially on shooter games it's getting bad very quickly on those.
Is this also how PWM cables and outputs work on FIRST Robotics RoboRio that run to Motor Controllers?
@linus I am thinking of buying a dell inspiron 14 5490, but I read on laptopmedia website that its display uses pwm (1000hz) and suggests that it is harmful, please share your thoughts on the same and whether I should buy this laptop or not?
Why does him and Linus have the same *Mannerisms?*
Literally they both have the same tone, movement, and range.
if theres a fan option in our bios AUTO/PWM, which one better ? and whats the different..
Can you do Operational amplifiers as fast as possible