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Its Dead Jim :-( That said, the diode might still be OK for optical sensing applications, I am looking into making some high altitude UV meters for which many LED'd but not O/C 405's are needed. I also found that sometimes if you take out the glass debris by decanning you can see how bad the...

If you can get the broken diode out intact I might be interested in donating you a few spare parts here (micros, etc) .. I have a need for LED'd diodes for my experiments in optical comms. Seems that as long as it has contact to the diode it should be fine, O/C ones aren't. PM me. Also I have a...

Hi all. Thanks to some do gooders over here, my "homemade" bike lights are now illegal. Seems that to avoid a £30 fine, the lights now have to comply with BS3648 which means most LED lights are technically illegal :-( Any ideas? The only approach I can think of is to buy the cheapest £18...

What about using a piece of pyrolytic graphite as the sense surface? This is near 100% absorptive at most wavelengths and is mechanically strong. Another useful tip,any old broken HP printer pre 2006 has an LM35DZ on the lid sensor PCB. This is good to 0.1 Celsius accuracy once calibrated, and...

Hi, hiw many $ for a couple of 445's? I am trying to build a laser etcher for making composite PCBs. thanks! -A

Hi all. I am after some small junction type blue 445 or 405nm diodes for an optical disk recovery device. Does anyone have a source for these? The ones used in the PS3 slim optics look promising but my one has negligible output power due to it being a used part. It has to be a canned diode...

I've had some success with "bricked" diodes ie ones which measure about 50 to 100 ohms on the meter in both directions. Usually only one tiny area of the junction close to the bond wire is "fried" and my technique has revived at least one burner diode to 30% of its previous power. Enough for a...

A possible method is to use an MC34063 to generate the required constant voltage, then add an LM317 in series with the output to limit the current with a capacitor between MC34063 output and ground and a 10K resistor between LM317T output and ground. This approach has triple redundancy so even...

Same problem here. I had to go through 5 different ebay diodes to find one which worked, you really need a spectrometer to get one exactly on 808nm then do a thermal profile to find out how to set up the feedback circuit. Then my working diode died due to overcurrent/etc and now emits about 9mW...

Does this mean filling a diode with liquid (ie ultrapure DI water or glycol) would increase its current handling ability? This would be an interesting experiment. -A

sorry double post, please remove

The general rule is 50% higher than the peak voltage. This ensures long capacitor life, however depending on the application and presence/absence of clamping zeners you can get away with less. A sensible margin in this case would be 20% > Vpeak (who found this out the hard way after having 8...

This would be useful for any application where constant current is required. e.g. electroplating, LED drivers, large format displays, etc. Is there a lower current limit? -A

This is an amazing piece of work, well done! One thing I'd add is a "tailbiter" aka "shut down very quickly" circuit. This is to stop your expensive diode frying if it 1) overheats, 2) something goes awry with the driver such as low battery causing open loop operation, 3) mechanical failure...

Tesla's early work in radio was so advanced that Marconi essentially copied Tesla's patents word for word when building his own equipment. Had Tesla managed to commercialise his discovery of resonant circuit based radio we would likely have had working continental wireless in 1902 and WW1 would...

Still got that "bad" diode?

Tesla's Death Ray machine This sounds plausible, as high intensity light hitting a ruby crystal with a simple mirror at each end will emit red laser light. Hypothetically, if Tesla came across a natural linear ruby crystal with plane defects at each end (not unheard of in the 1900s) then it...

Hi all. Seems that back in the 1900s Tesla was indeed experimenting with lasers. More specifically, single shot ruby lasers powered by a capacitor discharge. It appears that they worked by igniting a carbon button in the proximity of a ruby rod, generating very short bursts of red laser light...

"I never thought I'd see a resonance cascade, much less create one".. (Gordon Freeman) Actually, this might explain the Fermi Paradox. The average civilisation gets to the same level we are, builds a very large accelerator/fusion plant/etc and "accidentally" causes a massive explosion that...

Might work, plus 405nm LEDs are easy to get hold of. there was a discussion about using NIR LEDs as well, NASA discovered this effect. -A