• Lighting
  • I just finished testing over 90 different light bulbs...

I really like how you can quickly gather the information from the table format. If you measured these all by yourself, which device did you use to do so? From the supplied charts, I assume it's the Opple Light Master 3, since another member here has made a similar website using that device pretty recently.

    This is amazing! I sent a small donation in appreciation for the value of this! I dream to find something like this for LED lights used as backlights.

      a month later
      itchaboyagain changed the title to I just finished testing over 90 different light bulbs... .
      a month later

      Thank you @itchaboyagain for this. I sent a small donation a few weeks ago for this awesome resource.

      I appreciate testing halogen / incandescent lights as a comparison too, but the results were not what I expected.

      Some of the halogens like the GE 29W Halogen shows 10% flicker at 120Hz which I expect (60 * 2 = 120Hz, for USA electric):

      However, the GE 72W Halogen shows a much higher flicker rate of 10,000Hz and 0.2% flicker:

      I wonder if anyone here knows how to explain this? Why one halogen has 120Hz flicker and another 10,000Hz Flicker?

      9 months later

      This database is so cool!

      I think I'm extremely sensitive to small amounts of rapid flicker (I think flicker as low as 1% can affect me if there are abrupt changes in brightness). Though I'm not 100% sure about that.

      I didn't want to shell out $64 for a two-pack of Yuji bulbs (but if they eliminate my headaches then it would be totally worth it). So I bought the Philips Ultra Definition, 2700K, 1100 lumens 11w bulb.

      I don't have the Opple LightMaster, but here's the screen shot from @itchaboyagain's site.

      Image with no description

      Here's a screen shot from my setup (photodetector + oscilloscope) on DC mode. It shows pretty much the same thing. Mostly flat with dips at 120hz.

      However, on AC mode you can really see how much it flickers. Its range is 25 mv (goes up to almost 10 mv and down to a bit more than -15 mv).

      So the flicker percentage is about 4% (since on DC mode you can see that it's generating a bit more than 600 mv). And the drops are pretty sharp/jagged, indicating abrupt changes in light output.

      It seems like the main drawback of the Opple LightMaster is that it doesn't have the AC mode (or at least I'm not aware that it does), so you can't zoom in.

      Here's the bulbs that I use around my house. They are the Maxlite 60 w dimmable 2700k A19

      As a side note, here's a typical incandescent bulb that flickers about 10% but has very gradual changes in brightness.

      • JTL replied to this.
        17 days later

        GregAtkinson So the flicker percentage is about 4% (since on DC mode you can see that it's generating a bit more than 600 mv)

        What formula are you using to calculate flicker percentage exactly?

          JTL What formula are you using to calculate flicker percentage exactly?

          Unfortunately I've been inconsistent in my posts. A few weeks ago (including the post above) I was using (range)/(max) which is equivalent to (max-min)/(max). Over the past week or so I've been using (max-min)/(max+min), which seems to be more commonly-used.

          I think we should use (max - min) / max. The reason is that the formula (max - min) / (max + min) is not linear. It produces increasingly less differences the smaller the flicker gets. But we are especially interested in small flicker values, too. So dividing by (max + min) hurts our interest of making even small flicker values reasonably comparable.

          The first thing I did after purchasing the Fauser LiFli flicker detection device was to change its flicker percentage calculation from "/ (max + min)" to "/ max" (it offers this as a feature). Because the lowest percentage on its scale is 2% (which actually means 0% - 1.5%), and if I used "/ max + min", too many light sources would fall into this range. Light sources which when using "/ max" stay well above that range and are ones we probably want to stay away from.

          To me it seems "/ (max + min)" was an arbitrary choice to somehow account for the form or area of waves, too (in a very rough way).
          You can calculate a few test values to realize how (max - min) / (max + min) is producing values even for stronger flicker that are not very helpful for comparison (for example PWM that only goes down half of the amplitude would be equal to 33% flicker, when we'd naturally expect 50%) and how quickly calculation results approximate each other the smaller the flicker gets.

          IMO the only reason to use this formula is because as you say, sadly it seems to be widely adopted already and could make it easier to compare to some manufacturer's values. But again, for smaller values the differences become increasingly tiny, and no manufacturer is even bothering to print multiple positions after decimal point. So the smallest official value we could compare to is probably a very rough one like "< 1%" anyway.

            KM I think we should use (max - min) / max. The reason is that the formula (max - min) / (max + min) is not linear. It produces increasingly less differences the smaller the flicker gets. But we are especially interested in small flicker values, too. So dividing by (max + min) hurts our interest of making even small flicker values reasonably comparable.

            I totally agree! I'll use "(max - min) / max" and mention which formula I used going forward.

            23 days later

            Maxlite changed the manufacturing process and now the new 60w 2700k bulbs flicker pretty badly. There are a few old, non-flickering ones on eBay. Here’s an eBay listing that has them for about $2 per bulb with shipping.
            https://www.ebay.com/itm/155900291630

            Here's a couple pictures showing the differences. the newer (bad) box is smaller; the older (good) box is larger.

            I bought about 150 bulbs from various sellers that will hopefully last until my kids put me in a nursing home. It’s a large box, but still a very poignant reminder of my limited time on earth.

            • jen replied to this.
              7 days later

              GregAtkinson I tried the Maxlite 2700K 60W bulbs a couple weeks ago, but as @GregAtkinson and I expected they might given the spiky shape of the flicker waveform, they made me sick with concussion-like symptoms, although were definitely better than LEDs with high flicker. They were similar to other low-flicker lights that still injure me (data here). These were the MaxLite 2700K A19, E9A19D27/49/WS1, Code 14099718. So maybe they have the new, worse engineering? These had 0.17% flicker (calculated in the standard, misleading way used by the lighting industry).

              0.5 seconds (UPRTek flicker meter) with the x-axis at y=0:

              0.05 seconds and zoomed-in y-axis:

                jen So maybe they have the new, worse engineering?

                Unfortunately these are the old/better engineering. The new ones are way worse 🙁

                6 months later

                Your discovery about incandescent/halogen bulbs after the 72W mark no longer flickering is a fascinating tidbit. I bet that kind of data is exactly what lighting enthusiasts and professionals are looking for but struggle to find, especially those in part time electrical jobs. Will your database be accessible to the public soon? I imagine a lot of folks would love to dive into the data.

                  Any way to make it easier to find the ones available in European versions, or similar decent lists that does?

                    11 days later

                    async Hey Async! I'm hoping to expand this into European options, but I'm not sure of an equivalent right now…

                    Berezny Your discovery about incandescent/halogen bulbs after the 72W mark no longer flickering is a fascinating tidbit.

                    I have a question mark about this one.. what happens with 130v bulbs on a 120v circuit? They still consume the same power in watts, but the lumen output is reduced by about 25% due to the voltage difference so a 100w 130v bulb puts out roughly the same amount of brightness as a 75w bulb and I guess a 60w 130v bulb would appear like a 40w 120v bulb. So does the 100w bulb flicker or not when the voltage is different? Looking into it further, maybe I was mistaken about the wattage staying the same.. I read that it also goes down to about 85w but this would need to be tested with an actual meter to measure how much power is consumed at the plug before and after.

                    1. Only buy bulbs that can be sold in CA. Title 20 and Title 24 apply regulating flicker, CRI, life, etc. "CEC Compliant"
                    2. Smooth, low amplitude sine waves are perfectly fine. $18/bulb? Get out of here.
                    3. Don't buy the cheapest.
                    4. Don't buy the bulbs with the shortest life = more heat, worse components. If under 10 years, don't buy it.
                    5. Look at house brands of stores to save money.

                    I use Walmart Great Value 18 year bulbs which produce a sine wave. Did not test GV 9 year bulbs. Home Depot has Ecosmart bulbs but did not test. For those in Europe, I think Ikea has LED bulbs that were tested to be good.

                    dev