EEVblog #1252 – LED Panel Lighting Flicker Investigated

Dave investigates why his new LED panel lights are flickering on camera.
Teardown and measurement time.
PART 2: https://www.youtube.com/watch?v=9M76q2_VfDQ

Forum: https://www.eevblog.com/forum/blog/eevblog-1252-led-panel-lighting-flicker-investigated/

#LEDlighting #Flickering #Investigation

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49 Comments

  1. Robert Slackware on April 18, 2020 at 1:58 pm

    biggest problem I see is your gooberment paid for the good controller, and pocketed the kickbacks.

  2. Jeremy Lister on April 18, 2020 at 1:59 pm

    The second driver will be less efficient. The ic and transistor on the secondary is just an active linear filter which means power loss.
    True cure is a two stage switching driver such as PFC flyback to CV output with CC buck tagged on the output.

  3. saarike on April 18, 2020 at 1:59 pm

    Nice investigation!

  4. MrMaxeemum on April 18, 2020 at 1:59 pm

    Come on Dave, don’t just say don’t hack it and buy a better one. There is output of a transformer as in any other supply so what would be needed to give a satisfactory output?

  5. Liviu-Dan Timar on April 18, 2020 at 2:01 pm

    Could you convert to a half-wave rectifier so that it would flicker at 50[Hz]? :))

  6. davenz000 on April 18, 2020 at 2:04 pm

    Australian govt backs another winning scheme.

  7. capnthepeafarmer on April 18, 2020 at 2:04 pm

    Do you have a good recommendation for a flicker free driver or schematic to build your own? If you made one i would buy a few because my LED lights wreak havoc with my high speed cameras.

  8. Rýán Túçk on April 18, 2020 at 2:05 pm

    How can you now blame yourself for not having “checked out the drivers” when the schematics were likely marked ‘confidential’ long ago?

  9. rchandraonline on April 18, 2020 at 2:05 pm

    I don’t get it. Why is it on PSU inputs there is usually a full-wave bridge, but on output sides, there is usually only a single diode? Wouldn’t the ripple be a lot better (less) if it were a full wave on the output too?

  10. David Perkins on April 18, 2020 at 2:05 pm

    Dave, you mention the first circuit generating "100% Ripple", Would that be a peak-to-peak value of ~38 volts (?) (17:36)

  11. barneycarparts on April 18, 2020 at 2:08 pm

    Dave, Please do a tear down on why Infra Red Motion Detector Security lights fail so often. I have a collection of about 15 IRD Infra red detector flood lamps kits that just don’t turn on or false turn on, cycling on-off-on-off. Or just stay on for what seems to be forever.

    They seem to just last for 9-20 months and turn into garbage. They don’t trigger correctly Why? Temperature? crap caps? what? It seems that anything Honywell is crap, Intellisense is crap Brinkman is crap, Horrible Freight is crap.

     I do have ONE dual sense (two light intensities) IRC light that is very good ITT or Intellisesce is the brand. But, Anything under $45 is crap. why? I want a Motion Detector to last at least 8-10 years. Maybe you could do a "shoot out" of which Motion Sensors work the best.

    I would be glad to ship you some of my sensors that stay on too long or false trigger.

    We have wild animals like Fox that sniff our chickens and deer that eat our roses, and coyotes Buck Deer in heat who may charge/attack our dog, and Mountain Lions that roam and may harm our sweet old Labrador dog.

    Just curious if you would be interested in an analysis.

  12. Tall Sean on April 18, 2020 at 2:10 pm

    THANKS for this great video. This could explain why so many LED fixtures trigger my migraines.

  13. Xmc X on April 18, 2020 at 2:15 pm

    The proper way to fix these drivers is to hook them up backwards. Once the Magic Smoke is out replace them with higher-quality drivers.

  14. Michael MacDonald on April 18, 2020 at 2:15 pm

    "Concentration only for you" is from their website http://www.agt.net.cn/en/About/About_Us/ — ‘With "Concentration only for you" as the purpose of enterprise,use professional technology,focused attitude and dedicated spirit, we provide world class LED green products as our own highest pursue.

  15. C00ltronix on April 18, 2020 at 2:15 pm

    The PCB material is CEM-1. Inside is paper, but the binder is epoxy, not phenolic, and the outer layer on each side is glassfabric, usually 7628 type. CEM-1 can only be used for PCB without chemical through hole contacts, so it’s mainly used for single side PCBs. It’s still UL-V0 flame class (hence the red logo, UL-HB material has blue logos), same as FR4. "ZD" is the logo of Jinbao factory from Shandong. China also has a laminate type that uses a CEM-1 layer construction, but with phenolic binder. They call that 22F, it’s not an ANSI type and has no UL classification. I guess it’s not used in export products. Great video! Thanks!

  16. Gfast Gao on April 18, 2020 at 2:15 pm

    Hi Davi,
    Your early subscriber here. It’s all ready lighting better then before. But I still feeling a video about 20min long is still a little bit "too heavey" for a hobby level guy like me. I saw many compter programming tutorials under 15min. It’s always my better choice when your vids and them sitting in my playing list together. You have to admit, most of the time, people I planed to learn from you tube vids, but they actually do not have much time for it. I shorter vid will help people like me a alot.

  17. Robert Slackware on April 18, 2020 at 2:17 pm

    Well at least it doesn’t say "professional engineered" on it….. So no need to have it registered……

  18. Red Squirrel on April 18, 2020 at 2:18 pm

    What causes the current to ripple way more than the voltage? Even though it’s constant current I would not expect the current to drop so much for each cycle if the voltage is staying relatively high.

  19. Keif Fitz on April 18, 2020 at 2:19 pm

    Me: adds BFC to power supply output.
    Ripple: Ight imma head out

  20. David Perkins on April 18, 2020 at 2:19 pm

    13:09 – "All your LED panel drivers are belong to us." 🙂

  21. Skúli Sveinsson on April 18, 2020 at 2:20 pm

    The driver case look the same as Sonoff only longer.

  22. Alex Brand on April 18, 2020 at 2:21 pm

    50V secondary side cap and a max. 51V output rating, this is built to last forever 😀

  23. Xaranar on April 18, 2020 at 2:24 pm

    Isn’t 6700K a better colour temperature? It’s closer to pure white at 6500K. 5500 is a bit warm and yellow.

  24. Aravindan I on April 18, 2020 at 2:28 pm

    LED lights raw materials, mechine, training, Tamil nadu, cell: 9790148588.

  25. Stanislav Hájek on April 18, 2020 at 2:28 pm

    I don’t know, but wouldn’t be better to increase the input filtration capacity, there isn’t almost any, and when you’ll not have 50Hz ripple on the primary/input side, where from would come the ripple to the secondary/output side.

  26. Rýán Túçk on April 18, 2020 at 2:29 pm

    How can you now blame yourself for not having “checked out the drivers” when the schematics were likely marked ‘confidential’ already?

  27. Synergy7Studios on April 18, 2020 at 2:30 pm

    So your government is filling your homes with fire hazards? Nice. Classic government bullshit.

  28. Petre Rodan on April 18, 2020 at 2:30 pm

    For real now, the video looks infinitely better without those lights.

  29. Glenn Hamblin on April 18, 2020 at 2:32 pm

    The board is CEM-1 paper epoxy.

  30. Thor Lancaster on April 18, 2020 at 2:32 pm

    Power Factor 0.9 with no power factor correction circuit anywhere on the board? I’ll believe that when I see it.
    Edit: Oh yeah, the high power factor is due to… flicker!

  31. bigjd2k on April 18, 2020 at 2:34 pm

    Come back fluorescent all is forgiven… yes you can buy Philips 90,000 hour rated lamps which will outlast any LED (and be recycled afterwards), yes the higher efficiency magnetic ballasts weren’t that bad considering they were easily recycled, and the fittings were easily repairable by any sparks (unlike LED, they’re all different and the whole fitting usually gets replaced). We may have lowered our energy consumption a bit, but at the cost of much more e-waste and plastic trash.

  32. antilogism on April 18, 2020 at 2:34 pm

    "I’m from the government and I’m here to help."

  33. Karl Harvy Marx on April 18, 2020 at 2:35 pm

    At least the flicker is probably too fast for me to see. Flicker is very noticeable and irritating to me below 72 Hz or 75 Hz (forgot which). The US 60 Hz was bad enough, don’t know how people in 50 Hz countries survived with the old florescent tube lights. Does anyone know why some people seem to be immune to flicker and others see it clearly. And why is there person to person variation in when flicker becomes perceptible? Turnover rate of photo-pigments? Nerve firing rates? Beat frequency with EEG?

  34. jSkrat Nyarlathotep on April 18, 2020 at 2:36 pm

    12:17 how it is bridge rectifier, if there are only three diodes? what kind of bridge rectifier it is?

  35. onradioactivewaves on April 18, 2020 at 2:38 pm

    14:00 how is it AC coupled, do you have additional circuitry on the probe? The scope says ch1 is DC coupled.

  36. Starphot on April 18, 2020 at 2:40 pm

    Of course! Government subsidized panels and driver built by the lowest bidder! What else is new!

  37. capnthepeafarmer on April 18, 2020 at 2:40 pm

    Do you have a good recommendation for a flicker free driver or schematic to build your own? If you made one i would buy a few because my LED lights wreak havoc with my high speed cameras.

  38. Arlen Moulton on April 18, 2020 at 2:41 pm

    I have a RECOM RACT25-500 driver, 25w (50v@500mA) which would do the same job as this, I was VERY impressed with the build quality of it!

  39. Torgeir Fredriksen on April 18, 2020 at 2:41 pm

    Great video! How about making a video about how to design a proper LED driver? I

  40. YouTube YouTube on April 18, 2020 at 2:42 pm

    Wow

  41. whuzzzup on April 18, 2020 at 2:43 pm

    Flicker is the most important thing I check for new lights. Very important for LED lights, as – even with reputable manufacturers – lots of them have problems (even different series from the same manufacturer). This is why I don’t use LED here but fluorescent with a 40 kHz driver. This along with the fluorescent coating prevents flickering completely (well ok LED with a battery is definitely better, but you get my point for home lighting).

    So now your state installed more flickering LED bullshit that affects the brain. And they make you pay for it.

  42. Adam Keków on April 18, 2020 at 2:46 pm

    Hi!
    I wonder, why this video is in 60fps. I know that eariel videos are in 50fps for a reason. It elminates 100hz flicker.

  43. AnotherBrokenToaster on April 18, 2020 at 2:47 pm

    Anybody else misread the thumbnail? 😀

  44. Zoltán Kozma on April 18, 2020 at 2:48 pm

    This cheap construction is also used in newbuilds in the UK widely. And yes they are this crap so once you move into your shiny new flat you can start by destroying everything and bringing its ligts and wiring up to decent spec. A since 24W switching is performed by the darn one transistor there in an integrated package without cooling the operational characteristics of these crap drivers change as the temperature of the components increase and sometimes can cause the lights to cut out or just pass through some epilepsy-inducing low frequency flicker that is like a strobe light in a disco.

  45. Markus Epple on April 18, 2020 at 2:48 pm

    At 5:37 you see the rectifier "D81". On its output, two solder dots without holes is the PCB follow. Drill them and place a 450 volt capacitor there. Before powering it up, use a resistive load and measure the current it delivers with and without the capacitor. Also check if the drive chip gets unexpected hot. Never touch the operating or connected circuit to avoid electrical hazard.

  46. Bill Kerr on April 18, 2020 at 2:53 pm

    Free lights, and worth every penny of it.

  47. Peter Mortensen on April 18, 2020 at 2:56 pm

    The other two in this series:

    www DOT youtube DOT com/watch?v=9M76q2_VfDQ
    EEVblog #1253 – LED Flicker 2: Electric Boogaloo

    www DOT youtube DOT com/watch?v=dLlhoUHlnjE
    LED Flicker 3 – More Electric Boogaloo

  48. Stephan Spielmann on April 18, 2020 at 2:56 pm

    I get bullshit promoted ahead of your video. They promise an amazon-academy where I get a 6-7 digit revenue if I join their amazon-academy. I get everything I need with them. starting at advertisement and complete sourcing of stuff in China. I totally trust this 25 year old guy in rhw video with this. (I’m german and therefore trust this german guy)

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