I have never heard of a bridge rectifier failing in a such a way that it no longer worked, but also isn’t shorted out (or if not, burned up or fuse blown), and even that is very rare; diodes are pretty rugged devices, speaking from experience as somebody who has taken apart (and built) hundreds of electronics over the years, with virtually all AC powered devices using one. Maybe it was an unusual defect, or a power surge strong enough to cause an internal open circuit (but again, even a 1 amp bridge rectifier can typically handle a 30-50 amp (single cycle) surge so I’d expect to see other parts damaged).
Could be that it was cooked by heat emanating from a nearby resistor, or was a reject component in the first place - or maybe it’s only that the general build quality in What Exit?'s device is so poor that the rectifier chip looks like the culprit, but isn’t.
Diodes are pretty well know for overheating. It’s not surprising in this application and the description of the devices so far.
I would have thought electrolytic capacitors, since in my experience they are by far the most likely components to fail due to heat; as I said, I have taken apart literally hundreds of discarded electronics and diodes are rarely a problem, to the point where I never bother to test them when I remove them for reuse (curious how you know that diodes often overheat), but I have seen more than a few failed electrolytics (including in a CFL I had). Also, if the lamp really were getting hot enough to cause failure in an ordinary diode, the LEDs would have failed long before, since standard LEDs (the kind used in corn cob bulbs, look like this) are only rated for 85°C or so, compared to 150°C (sometimes 175°C) for silicon diodes; electrolytics on the other hand, even those rated to 105°C, only last a few thousand hours at that temperature (decreasing by a factor of 2 for every 10°C higher, so 150°C would result in a lifetime of just 88 hours for a standard 2,000 hour 105°C capacitor; to last for 50,000 hours in an LED bulb, the temperature needs to be kept below 60°C).
ETA: Like **Mangetout **said, it could just be a very cheaply made part or reject (fraud is very common with electronic components, mostly with more expensive parts though).
The voltage drop across an LED varies with operating temperature. I believe the have a positive temp coefficient. From the tear down video it’a clear that there’s nothing to compensate for this, perhaps explaining the reduction in light output over time.
The folks at switch light bulbs seem to have addressed this by filling the e closure with liquid coolant. They look nice and high tech. I’m anxious to try one, if they ever become commercially available.
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I still maintain that if we’re in fact going to ban incandescent lamps it would be better to ban the socket rather than the bulb. The phaseout would take a a lot longer…
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It’s starting to happen. We were shopping for light fixtures recently, and a lot of them now have changed over from the traditional “A” socket to candelabra sockets or GU24 bi-pin CFLs, so it’s impossible to use standard bulbs.
This is a bit difficult to follow, but you seem to be saying that Cree is a Chinese company. They are actually based in Durham, NC and at least some of their bulbs are manufactured there.
I- trying to be a good, eco friendly person- picked up some LED bulbs on my last light bulb run at the Home Depot. Sweet merciful christ- the light was AWFUL. I mean, it was full on, bright hospital white in my house. Ok, like the world’s brightest, whitest hospital ever. I took the LED bulbs out, put them in a drawer, and put in traditional ones.
Just bought my third 40w equiv. LED from Home Depot tonight for $7.97. My bedroom fan now dims nicely or lights the room very well and all for 27w max. I’ve been very happy with these Ecosmart bright white A19 LEDs.
i have a dimable Sylvania 8W (40W equivalent) bulb, white light (3000K). a very good reading or task lamp.
It always pays to note the color temperature of non-incandescent lamps before buying them - the light varies from blueish to greenish to yellowish, depending on the manufacturer.