Tearing Down A Failed LED Bulb

todd-harrison-led-bulb

[Todd Harrison] was thinking of replacing some incandescent light bulbs in his house with LED models, so and his wife picked up a single candelabra bulb to test before they spent the cash to swap them all out. The bulb died in about a week’s time, so [Todd] got out his trusty electronic disassembly device (his hammer), sharing his post-mortem examination with us.

After taking a cursory look at it, [Todd] found that the circuit powering the bulb was not overly complicated. A small bridge rectifier along with a few caps and resistors are all that was used to power the device, making it’s failure a bit puzzling. When [Todd] wired it up to his power supply, the bulb lit up, much to his surprise. His best guess as to why it died is that the shrink wrap around the PCB managed to cause a short, though he also noticed that one of the bridge rectifier’s legs was not soldered down.

He started tooling with the light to find out more about it, but he managed to blow out a handful of LEDs in the process. All in all the LED lighting swap was a disappointment, but at least he had some fun along the way!

Continue reading if you’re interested in seeing [Todd’s] diagnosis in its entirety.

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Imploding Vacuum Tubes For Science

The researchers at Brookhaven National Laboratory are looking for a way to harden photomultiplier tubes. In order to make a more durable tube the researchers decided it would be a good idea to first observe how the tubes are failing. So they got their hands on an old torpedo test bay and smashed some bulbs inside of it. Check in after the break for some high fps bulb smashing.

Photomultiplier tubes are used in massive quantities to detect the highly elusive neutrino particle. The problem is when you have 50,000 photomultipliers submerged in pressurized water the the collapse of just a single bulb can cause a shock wave of destruction. This is what happened in japan in 2001 when a maintenance worker unknowingly compromised a single bulb in a 11,000 bulb array. When the tank was repressurized that single compromised bulb caused them to lose 7,000 more.

[via wired]

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Surgical Microscope Gets LED Retrofit

[Roberto Barrios] picked up a surgical microscope to add to those other fun lab toys you seen in the background. These work very well when soldering small components because they don’t have to be as close to the viewed objects as traditional microscopes. But [Robert] didn’t care for the heat generated by the incandescent bulb so he build his own LED replacement. If you recognize his name it’s because we saw a beautifully crafted in-visor GPS system that he built back in April. This project exhibits the same level of craftsmanship in which he utilized the base of a spare bulb to add an LED, heat sink, and driver board that is adjustable on all three axes.

He also mentioned that he overhauled his site design and it now plays nicely with all browsers.

IEE Clock

The IEE clock looks somewhat un remarkable at first glance. Upon closer inspection though, you’ll find out that there are 12 light bulbs crammed in there for each digit. The bulbs sit behind a curved lens with the numerals on it. When the appropriate one is lit, it projects the number on the front of the clock. While it isn’t new, it is certainly new to us. It is also interesting that you set the time by rotating the little dial on the top right. While it may be easier to set the time that way, it seems that it would be prone to getting nudged on accident.

[via the Hackaday Flickr pool]

Cheap Projector Repair


[Ryan] sent in this writeup on some DIY projector repair. The write-up is a little hard to follow, but maybe it’ll inspire some future projector landfill saves. [Dissident] replaced the light bulb and ballast in an older DLP projector with some salvaged MR-16 hardware from an even older over head projector. The main trick required was to bridge the trigger leads that tell the projector that the bulb is on and working.