PWM dimming is the devil and that you should avoid every monitor or TV that utilizes it.
if you don't know what PWM dimming is, it's a cheap technique used to control a monitor's brightness, and will cause a display to flicker like a motherfucker. when you lower the brightness on a PWM monitor, it'll just rapidly turn the backlight on and off to create the illusion that the backlight is dimming. if you're not careful, that shit will cause serious eye fatigue and potentially ruin your eyesight. do you really want to wear grampa glasses in your 30s?
now, if you read up on PWM dimming online, you'll notice that a lot of articles mention that pwm actually has a bunch of benefits, as opposed to the more expensive (and superior) dc dimming. those are complete bullshit lies and exaggerations. the only real purpose PWM dimming serves is to keep manufacturing costs down. those 'benefits' are just made-up bullshit that companies feed the media and customers to justify their greedy practices. they're just trying to sell you crappier TVs for a higher price.
if you want to know if your monitor uses PWM, simply wave a pen in front of it. if you notice a strobe effect as you wave the pen back and forth, you've got a pwm monitor. so throw that shit out and get a proper monitor. don't let the panel jews ruin your eyes.
btw, anyone who defends PWM dimming is most likely a corporate shill trying to damage control, and should not be trusted.
We get it, you had a class on signal processing today.
Luke Powell
fucking lol
Kevin King
PWM is fine as long you use a high frequency, like 10Khz. PWM under 1Khz is just for shit like powertools.
Andrew Nelson
because this is exactly what they do.
Evan Lewis
CRTs are the only thing I’ve seen that visually had a flicker, but even that was only under 75hz Even 120hz black frame insertion on an LCD doesn’t really have a flicker OP must be dealing with some real shitty LCDs with dumbass engineering
Juan Thomas
just another lie to make pwm dimming seem more "premium". PWM is more commonly seen in budget panels.
Adrian Williams
hello friend,
I understand that you're buttflustered about something.
However please do consider that you might have a fundamental misunderstanding of how LEDs work. If someone is selling you "DC dimmed" leds, they're either lying to your face, or you're genuinely trying to tell us that yellow backlighting is superior to white backlighting.
Cameron Baker
They basically say it's worthless in that article, why the fuck would they try to pass it off as premium
Oliver Perry
>change PWM frequency to literally anything over 200Hz Wow suddenly no human can see the flickering and it literally doesn't matter at all.
>white backlighting. most monitors are calibrated to use blue backlighting oob, even DC dimmed LEDs. I would know since I own one. the yellow led thing is a myth, just calibrate your monitor properly, brainlet
Isaiah James
>limit DC current to LEDs >they get dimmer What exactly does this have to do with yellow vs white lighting?
Thomas Peterson
no, they don't but ok
Jaxson Brown
This was a decision I made when getting a monitor. I chose dell because they didn't use it at the time. Coming from work to that and the difference is crazy. Pain in eyes which mysteriously goes at the weekend when I'm off.
Jayden Parker
LEDs don’t have to be dimmed with PWM directly acting on the LEDs, it’s possible to have LEDs powered trough a constant current driver that uses a PWM signal to control the voltage output of the driver as to eliminate flickering
Dylan Lopez
>They basically say it's worthless in that article so why do they use it on every tv they produce?
Carson Stewart
High frequency PWM is entirely fine. You're not going to perceive any flicker at >20kHz, or even way below that, though >20kHz is a nice number to aim for since it also guarantees that any mechanical vibration in the circuit (like coil whine) will also be at a frequency beyond human hearing range.
Ian Nelson
You've demonstrated to everyone here that you are an idiot. Congratulations.
Every lightbulb in the world flickers at 50/60Hz, except fo rthe rare DC setups, like automotive, movie/TV. LED displays on calculators and watches are PWM-controlled. Your TV scans as does your PC display. PWM is the least of your problems.
Alexander Garcia
Is it 2009 again?
Asher Harris
white leds shift to yellow when underpowered and blue when overdriven. you're meaning to tell me that you calibrated your screen for every dimming level? calibration doesn't fucking help when your blues get clipped.
of course it's theoretically workable and I imagine you can imagine it in your little heads that it be like this but it ain't for the simple reason that it's fucking stupid, and no one would buy it because it looks like shit.
yes, leds need a DC power supply, from which a high frequency PWM signal gets generated. You will however see flicker when the the caps in your power supply get shot to fuck and you start to see the AC mains waveform leak through. This is probably what OP is complaining about.
Liam Nelson
>underpowered >vs being on or off brainlet
Samuel Ortiz
I agree, some monitors actually advertise flicker Free as a feature now.
Henry Myers
>white leds shift to yellow when underpowered and blue when overdriven I got my degree in electrical engineering, in the US, and I have never, ever, ever heard this before.
It seems like something that important would have come up at least ONCE in all the times we talked about LEDs, backlighting, current drivers, control circuits, and everything else related to LEDs. At least once.
So, do you have a source for this? Or are you going to post a retarded youtube video of people dipping an LED in liquid nitrogen and saying "lmoa look it turned blue im right about this"
"correlated color temperature (CCT) of solid-state lighting changes with voltage" "The established solution is to eschew analog dimming in favor of a digital technique such as pulse width modulation (PWM)"
Luke Foster
>you really want to wear grampa glasses in your 30s Already am at the ripe age of 20, oh well.
it's phosphor scintillation saturation if you wanna google more.
congrats, your rinky dink ghetto ass diploma is worthless.
Nathan Turner
i imagine this is only a problem with low quality LEDs. pwm-free monitors are probably more expensive because they require more expensive LEDs that are resilient againt color shifting.
Carson Edwards
>i imagine this is only a problem with low quality LEDs. pwm-free monitors are probably more expensive because they require more expensive LEDs that are resilient againt color shifting.
>The conclusions that the researchers reported were that it was the junction temperature change of the LED that caused the chromaticity shift, and the temperature was influenced by the PWM duty cycle. >"yeah but it's only DC regulation that causes color shift" t. you Are you retarded?
Junction temperature is what causes color shift. It doesn't matter if you're using PWM or current driving, they both do the same thing; limit the average current through the LED. That affects the temperature, and therefore the color. Both methods do that.
Besides that, your source does a pretty shit job of explaining just how much color shift there actually was. And where it does give hard numbers for that in some nonsense esoteric color shift unit instead of actual color temperature like a real human would use, the difference is tiny. Extremely tiny.
And surely if color shift were such a big deal, at least ONE major manufacturer of LEDs would list it in their spec sheets? Surely that would come up, at least once, if it actually mattered in any real-world application?
But it doesn't. Very interesting. Care to explain that?
>posts a source completely unrelated to what we're talking about Be silent.
from that source however: Direct Current (DC) control, which does not cycle the backlight off and on at all, but can be more complicated to implement. In some cases there is also difficulty controlling the colour in darker images and so DC backlight control is less common
I still think it's snake oil though, maybe I have a low flicker-fusion threshold.
Jeremiah Harris
>name one "pwm-free" or "dc-dimmed" monitor so we can move forward I'm telling you it doesn't fucking matter. We were talking about color shift, you said "hurr no you can't use DC dimming because le color shift", I showed with YOUR OWN SOURCE that you were wrong - PWM or DC does not matter, they both color shift the same because it's junction temperature (not the method of brightness control) that determines color temperature.
>you've set up a straw man on a barren field. What?
Evan Hill
>PWM is fine as long you use a high frequency, like 10Khz. "eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee" Where is that noise coming from? "eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee"
Connor Gray
>most monitors are calibrated to use blue backlighting oob, even DC dimmed LEDs. I would know since I own one. the yellow led thing is a myth, just calibrate your monitor properly, brainlet wat. I can't even tell what you're arguing.>white leds shift to yellow when underpowered and blue when overdriven. No. They can shift slightly, or a lot, depending ont he LED, but it can be in either direction.
Imagine being this autistic >that shit will cause serious eye fatigue and potentially ruin your eyesight Good goy, buy new and more expensive flicker-free monitors
Jason Nelson
>it's junction temperature (not the method of brightness control) that determines color temperature. No. Not just. Forward voltage matters in addition to temperature.
Kayden Brooks
lol
Noah Jackson
good luck shitposting when you go blind
Jonathan Price
oh noes what is I going to do!!!!!!!
Thomas Harris
The original Nexus 7 had some bottom of the barrel cheapo PWM dimming, and boy it drove me fucking nuts. I'm usually not that sensitive to display quality differences, but I could literally see the screen turning on and off rapidly when the brightness was lowered to less than 30%.
Asher Jenkins
U2713HM
Carson Stewart
This is a new level of tin foil. I'll take my chances.
Daniel Nelson
ok enjoy your inferior chink products and eye strain. why don't you get some speakers that randomly raise and lower the volume to go with your crappy monitor?
If I don't even [and won't ever] notice the volume change then sure dude.
Hunter Brooks
Btw most of the thinkpads shilled here use panels with horribly low frequency pwm. Only recently lelnovo actually started doing something about it on some of their newer models. Some people apparently don’t notice it, but I’m very sensitive to pwm and had to return my x230 because it was unbearable to look at despite being great otherwise. I was literally getting nauseous just looking at it for like 20 minutes.
Jordan Gomez
you won't but after 10 years you will develop tinnitus
Colton Cox
>electrical engineering Are you by any chance the same retard who thinks Quantum Mechanics is just caused by current leakage
Evan Thomas
what's a low-pass filter?
Luis Richardson
This
Adrian Campbell
this is like known issues since the inception of LCDs. only LCD fanboys are unaware or ignore it. here is a 1/1000s pics taken on HP LCD with PWM.
now, monitors flicker at a much higher frequency than what is considered harmful, but if you could choose between a potentially harmful thing and a thing that's completely harmless, what would you choose? there's no need to let your eyes get raped by disco backlights when flickerfree alternatives exist
i literally think its bullshit. lights in your house flicker at 60fps and thats perfectly fine for some reason, yet your monitor doing the exact same thing is somehow worse
also consider that natural sunlight on a sunny day in hawaii is like 100x more powerful and has a much much broader electromagnetic emission so if anything, sunlight is what fucks your eyes up
I think the same thing about the 'blue lights on monitor screens hurts your eyes' thing too
Justin Sanders
>lights in your house flicker at 60fps your lights don't turn on and off at frequent intervalls, retard (unless you use dimmable leds, which you shouldn't)
Adam Johnson
It's only a problem if the frequency is too low, OP is retarded and thinks LEDs have instantaneous response.
Adam Cook
>also consider that natural sunlight on a sunny day in hawaii is like 100x more powerful do you normally look straight into the sun for several hours per day?
Luke Wright
I dont even mean looking at the sun. Just looking at the road while driving, especially on a snowy white day. Without eye protection you literally cant keep your eyes open. Your monitor cant even get close to that level of brightness. Even in a dark room with max brightness, your eyes can get used to it. It does hurt, I will say, but you can turn the brightness down and its A-ok
Hunter Martin
except he's wrong.
Leo Carter
you dont even know all the different kinds of lights I have around my house. and yes, they are all flickering because they work off of fuckin AC current. if you had a high FPS camera you would see that yes, they do turn off for a breif moment
Jeremiah Bennett
>but you can turn the brightness down and its A-ok unless you use a pwm monitor, in which case the monitor will blast your eyes with full brightness AND flicker like crazy
Caleb Richardson
CRTs are big honking analog devices and naturally have to rely on the tolerance of the electrical components inside for their performance Nothing lasts forever and as shit ages it loses it's tolerance and you get a progressively worse and worse image as the focus, geometry, convergence or anything really goes out of wack LCDs on the other hand stay pretty much the same no matter there age up until they die, of course the components inside are no less susceptible to age but being a digital apparatus it's much harder to fuck up 1s and 0s than something analog
Tyler Clark
>if you had a high FPS camera you would see that yes, they do turn off for a breif moment no they don't retard. they may flick between 99 and 100 percent brightness or some shit but they shouldn't turn off completely.
if they do you're using some garbage chink lights
Nolan Bell
don't forget the inevitability of getting cancer from aggregated radiation poisoning. perhaps that's the reason we see such an outbreak of it these days.
You do realize the output of a PWM controller can be smoothed out with a capacitor, right? Come on, it's basic electronics...
Henry Wright
I don't get it, while flickering in the 1-20 Hz range CAN cause problems in those sensitive to it what does this have to do with PWM in screens which operate at 60Hz or greater?
Not shill but genuinely curious since there have been a few documented helicopter crashes due to pilots staring at the rotor blades in front of the sun but the fact that there isn't an epidemic of people getting sick from staring at LCD screens for extended periods of time.
Matthew Evans
1) No monitor uses it anymore. 2) What are capacitors for PWM controllers.
Fuck off retard.
Landon Reyes
>potentially ruin your eyesight Stop with those myths, nothing but physical harm can ruin your eyesight, stress while reading in the dark or staring at a PWM monitor won't. There have been studies about this, this isn't 1912.
PWM will just make your head hurt. Avoid it if possible.
Dominic Ortiz
>1) No monitor uses it anymore. literally 90 percent of tvs use pwm. go ahead, check your own tv >PWM controller i have a better idea, why not just get a monitor that's not garbage. yes, they do exist
Joseph Butler
>if you want to know if your monitor uses PWM, simply wave a pen in front of it. if you notice a strobe effect as you wave the pen back and forth, you've got a pwm monitor. so throw that shit out and get a proper monitor. don't let the panel jews ruin your eyes. But I specifically turn backlight strobe on at higher FPS for better motion....
>literally 90 percent of tvs use pwm. go ahead, check your own tv Nope. I'm not a retard like you who buys shit without checking and later rants on Jow Forums that he fucked up.
>i have a better idea, why not just get a monitor that's not garbage. yes, they do exist Dimming PWM controller, as in LED lights you might use around the house. You simple put a cap at the end of the controller output and you're fixed.
Isaiah Powell
haha i love the naivety of plebs.
Eli Martinez
Hey FUCKTARDS: set your screen to 100% brightness, all flickering gone.
Jason Bennett
>literally 90 percent of tvs use pwm. go ahead, check your own tv >monitor is TV is monitor is TV we call monitors and TVs differently for a reason
