Not long ago, "American engineers dismantled the Chinese-made LED bulbs". A friend wrote a message saying that the design is a conscience, and some of them have it; still did not see, who killed the LED? Below the original English text, dozens of netizens commented on the root cause of the troubles in the lively. The following selection of some people's speeches translated into Chinese, I hope to gain something for everyone.

Not long ago, the EDN US version editor dismantled the broken LED lights at home and wrote a dismantling "Teardown: What killed this LED bulb?". After seeing this, I compiled and translated this article and published it in Chinese. On the version, after many readers saw it, the comment said that it still didn't see it. Who killed the LED?

Oh, yes, forgive me for click bait, and I will change the title slightly. "American engineers dismantled Chinese-made LED bulbs: Did you reduce the cost?" The result was a friend who said that he didn't see how to cut corners and friends. The message said that the design is a conscience, and there are some.

Below the original English text, dozens of netizens commented on the root cause of the troubles in the lively. In fact, it is not important to understand who killed this LED. Everyone spends so much time and patiently with a light bulb of a few dollars, which fully reflects the natural love of our electronics engineers for professionalism. It is this passion and commitment. It has promoted the rapid development of the global electronics industry.

The following selection of some people's speeches translated into Chinese, I hope to gain something for everyone.

Netizen slotef

D7 is gone, it would be a problem if all the beads are connected in series. But why are you missing? There seems to be a trace of heat on the board.

Perhaps the ceiling installation (LED down) is not ideal for LED bulbs (no heat dissipation), the heat generated during the work is baking the components, so the weakest one hangs and the whole light does not illuminate.

User RBENG

The board looks like a hand soldered, possibly with lead-free solder. Manual soldering is difficult to solder with inexpensive lead-free solder, and high-quality lead-free solder (my personal preference for silver-bearing KESTER) is expensive, as can be seen by the naked eye, very low manufacturers should be less likely to use . There should be cold solder joints on this board.

The heat dissipation is very poor. The LEDs will heat up during operation and may be hot enough to break the solder of an LED (these LEDs appear to be connected in series on the PCB).

I suspect that the life prediction for LEDs is based on a 25-degree working environment. According to the general rule of law, the life of an electronic component is reduced by half for every 10 degrees.

If the LED is operating at 100 degrees, the lifetime of 10,000 hours will drop dramatically to about 2,500 hours.

User KKing1

I agree with the "bad welding" speculation.

As someone said, C3 seems to have one end not welded.

I also suspect that there is no connection between R4 and R7.

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User UweZi_

The assumption of Cylone0 is completely correct, and D10 is the cause of your failure. I've seen similar LED lamp failure modes, but those that use a capacitive dropper instead of a transformer circuit—a simple spike on the grid can cause a malfunction. Because all the LEDs are connected in series, one of the broken lights will be finished.

The number and size of LEDs impressed me a lot, and the manufacturer had to supply a serious excess of 800 lumens. 800 lumens of LEDs (11 beads) means 73 lumens per generation.

The heat sink compound between the PCB and the bottom looks a bit suspicious and sparse.

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