Fluke diode from eBay 405nm 5mW laser?

[jamiphar]

I'd recently bought a few pen-style low-power pointers from an eBay seller - two 532nm and one 405nm. On Sunday I decided to tear the 405nm one apart to use the diode in another host and to extract the boost driver for examination.

Since I mainly bought the laser for the driver it came with, I wasn't too worried about blowing the diode. I hooked up a rkcstr driver and set the current to 80mA. It handled that just fine, so I decided to push it further by cranking it up to 180mA. Surprisingly, this diode seems to be handling the power with ease. It has had about 30-45 minutes of runtime so far with no signs of failing.

I'm going to leave it at 180mA for now, but I might set it a bit higher if the diode's still kicking after a couple weeks. Has anybody else seen something like this?

 

[daguin]

Diodes vary GREATLY from one to another. It is NOT uncommon to find one that will survive at higher currents. It IS uncommon for Chinese companies to put an expensive diode into a cheap pointer.

I found an SF-AD110 (60mW) that survived at >200mA for 60 hours. The overwhelming majority (>98%) died at around 90mW. Should we be excited about my single example of high current survivablity? Do you think that 60 hours of runtime is an acceptable lifespan for a diode?

We look for currents at which the majority of diodes can survive >300 hours for pointer work. We also need significantly more than one example to even begin to understand a diode. Finally add to these problems that the Chinese will use whatever diode they can get that will do the "rated" output for a quick burn.

Posts like this encourage NooBs to pot mod their lasers. This generally resuilts in the destruction of the laser.

How about you write back when you can give some identifying info for the diode AND it exceeds 300 hours of "on" time

Peace,
dave

 

[jamiphar]

I get what you're saying. I didn't mean to say that maybe more of the DX/eBay lasers are like this (or to encourage pot-modding for newbies), I just wanted to share the info on this specific "freak" diode.

I'll rack up some hours on this and check back in with the results. When testing, do you run your diodes continuously (with proper cooling), or are the hours accumulative after many on/off cycles?

 

[daguin]

I get what you're saying. I didn't mean to say that maybe more of the DX/eBay lasers are like this (or to encourage pot-modding for newbies), I just wanted to share the info on this specific "freak" diode.

I'll rack up some hours on this and check back in with the results. When testing, do you run your diodes continuously (with proper cooling), or are the hours accumulative after many on/off cycles?

Initial tests are run continuously. After we have an "idea" of the correct current, then we build pointers and test them pout fairly real world. IgorT built a test machine that cycles the diodes off and on. but there aren't many of those around

Peace,
dave

 

[jamiphar]

Sounds good. Maybe I can connect a power supply to a timer circuit to switch it on and off.

 

[Tech_Junkie]

"freak" diode.

.....:thinking: