| General > General Technical Chat |
| Explain to me the (de?)-evolution of LED lightbulb technology |
| << < (6/15) > >> |
| Rick Law:
It is to be expected. CFL light bulbs also went through this expensive-to-cheap phase. Nearly 30 year ago, I got a 4 pack of GE CFL, 60W equivalent lumans at about $15 each. Two of them are still working! The home HomeDepot/Walmart CFL's bulbs these days dies left and right at a youthful age. I've a couple of those ~3 year old CFL with so much brightness lost it is kept as emergency - in case I needed a bulb when stores are closed. Most of the others hardly last past 3 years old. I expect the HomeDepot/Walmart LED lights (60W equivalent lumans) to be dying of young age as well. |
| rsjsouza:
--- Quote from: Tomorokoshi on March 23, 2021, 08:39:06 pm --- --- Quote from: andy2000 on March 23, 2021, 08:19:16 pm --- --- Quote from: Sal Ammoniac on March 23, 2021, 03:45:46 pm ---I wonder if this race to the bottom price-wise results in LED bulbs that generate lots of RF noise? I wouldn't be surprised at all if it did. So now we have a product that generates two kinds of pollution: RF pollution and light pollution. --- End quote --- I recently bought some new LEDs to replace some early ones that were starting to fail. Coincidentally, around the same time I noticed a lot of interference on a vintage analog TV in the next room that gets used to watch the news. There were very noticeable wide horizontal noise bars moving up the picture. It turned out that the new bulbs were causing the interference. The set is fed using a shielded coaxial line, so I was surprised so much noise was leaking in. With the coax unplugged, the usual snow was completely obscured by the interference. Out of curiosity, I used my spectrum analyzer to look at the interference. This was with just an dangling probe as an antenna. You can see the FM band on the left side, and a couple of ATSC TV channels on the right. The bulbs were generating interference over the entire spectrum up to about 500 MHz. Needless to say, they went back to the store. The old bulbs generated no visible interference. --- End quote --- Feit. I could have guessed that. Those fail the quickest for me. --- End quote --- That is my experience as well. Nasty things. Thank you andy2000 for sharing the interference spectrum profile. I found out that CREEs are still well done. I did a video a while ago about a 2018-era 60W equivalent bulb and it had a real constant current source. If you are interested, check the circuit at about 10:30 of the video below (in portuguese only, sorry) |
| amyk:
Some more discussion on the Dubai Lamp here: https://www.eevblog.com/forum/chat/the-dubai-lamp/ Capacitive droppers are cheaper and in my experience more reliable than the switching ICs. I have some lights using them and they've lasted most of a decade. BigClive also made this video not long ago, which is mostly about a related topic, but one thing caught my attention: lights with socketed electrolytic capacitors: I don't think I've ever seen socketed capacitors even in equipment designed to be serviced, much less a cheap throwaway lightbulb. |
| james_s:
I had a lot of Feit CFLs that didn't last very long either, I actually fixed a bunch of them at the time, it was a mylar capacitor between the two cathodes used as part of the starting circuit that would short. For LEDs I buy mostly Cree and Philips, I've generally had good luck with those. I have some of the EcoSmart (Home Depot house brand) bulbs from way back in 2010 and a few modern ones, all of those are still working surprisingly. |
| BrokenYugo:
They socket the filter cap and mains connection to speed up/cheapen assembly, those reflow compatible sockets must be cheaper than the cost and/or time of hand soldering. |
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