Can an expert comment on the specs of this UV chip?

[ptolemy]

I found a light for sale that's advertised as a 365nm. Price wasn't too bad, so I called the company and got the spec sheet of the chip.

They wouldn't say who makes it, they did say it's either Chinese or Japanese supplier.

I compared it to the Nichia chips specs, and this seems to be little above their lower end offering and much below of their big boys.

I am attaching the sheet, so If someone can comment on the details...

If it's worth it, it might be a easier/quicker way of getting quality UV light instead of waiting weeks and weeks for chips to arrive and then custom building a light.

Thanx

 

[MrGman]

That's real UV, if you are planning on making a light to see what things fluoresce (glow) under that you probably want to put no less than 5 of those in parallel to have enough energy in that spectrum to do some good. Make sure you don't stare into it wondering why it looks so dim if you can see anything at all. That will light up the secret strips in US currency and drivers licenses and UV dyes. Its much better than the UV LED's that are in the 390nm wavelength spectrum.

 

[ptolemy]

That's real UV, if you are planning on making a light to see what things fluoresce (glow) under that you probably want to put no less than 5 of those in parallel to have enough energy in that spectrum to do some good. Make sure you don't stare into it wondering why it looks so dim if you can see anything at all. That will light up the secret strips in US currency and drivers licenses and UV dyes. Its much better than the UV LED's that are in the 390nm wavelength spectrum.

Ya, the light they sell has 5 of these, indeed.

I am more curious on the quality of these... Are they same low power uv led's that you buy on ebay for $5 (although in thr 365 range), or little bit higher end.

By looking here http://www.nichia.com/product/led-uv-smt-lt.html
I see that the cream of the crop is the NCSU033A which has 250mW optical power and can draw 500 mA

They also have more basic version which only has 2.0mW and draws 20mA

Hnece I was wondering if an expert could compare those 2 to this. Seems to be this one is bit more powerful than basic nichia but nowhere near as powerful as their top model.

I am right?

 

[MrGman]

Who knows the quality of what they sell on ebay. Not even going to bother looking at that. That is a buyer beware market.

This item is a 6mW power consumption device at the rated 20mA. Its slightly better than the basic 2mW rated device. Its no where near the output of the 250mW, so you are right that its just above the basic chip and not much else. Anything you see packaged in clear plastic lens or bulb can't handle much power and was not designed for much power. You would really want to put about 30 of these together in parallel to start doing something useful for UV inspection.

 

[Anai]

Ya, the light they sell has 5 of these, indeed.

I am more curious on the quality of these... Are they same low power uv led's that you buy on ebay for $5 (although in thr 365 range), or little bit higher end.

By looking here http://www.nichia.com/product/led-uv-smt-lt.html
I see that the cream of the crop is the NCSU033A which has 250mW optical power and can draw 500 mA

They also have more basic version which only has 2.0mW and draws 20mA

Hnece I was wondering if an expert could compare those 2 to this. Seems to be this one is bit more powerful than basic nichia but nowhere near as powerful as their top model.

I am right?

I am sure is 100% made in China. I asked a friend of mine. He bought 20 of them, he keep uses it for about 10 hours a day, and about three weeks later, 8 of them dead.

 

[ptolemy]

Who knows the quality of what they sell on ebay. Not even going to bother looking at that. That is a buyer beware market.

This item is a 6mW power consumption device at the rated 20mA. Its slightly better than the basic 2mW rated device. Its no where near the output of the 250mW, so you are right that its just above the basic chip and not much else. Anything you see packaged in clear plastic lens or bulb can't handle much power and was not designed for much power. You would really want to put about 30 of these together in parallel to start doing something useful for UV inspection.

thats what I assumed

thanx:>

 

[PhotonWrangler]

I am sure is 100% made in China. I asked a friend of mine. He bought 20 of them, he keep uses it for about 10 hours a day, and about three weeks later, 8 of them dead.

I'm guessing they're direct-driven (and overdriven) if they stopped working after 8 weeks. You could buy one and try dropping a regulator puck in there but I'm not sure it will be worth the trouble.

 

[MrGman]

since they are meant to be run at 20mA a simple resistor based on the battery voltage you want to start with would be just fine. They show a max current rating, I would not go more than 1/2 of that for continuous use. So I would not push these over 40mA.

So lets say you had a 3AAA NiMH batteries at 3.6V under load of 40mA. The voltage drop to the device under that load is about 3.1V, you have 0.5V at 40mA to drop. that is a 12.5 ohm resistor. That's only 20mW of power so a 1/4 watt resistor would be more than adequate, actually so would a 1/8 watt.

but lets say you really want to drive 10 of these in parallel you sly devil you. Thats 400mA. Using 3AA batteries NiMH at 3.6V under load at 400mA and each of the LEDs is 3.1V in parallel X 10 is still 3.1V. You now have 0.5V at 400mA you want to drop. That is a 1.25 ohm resistor. That is of course 200mW across the resistor so you would want to use a 1/2 watt resistor. The beauty of this is as the voltage drops you go down gradually to the optimum 20mA setting per LED and the batteries will probably deliver you a fairly useful run time. The resistor isn't wasting too much power for itself. The 200mW for the resistor is compared to 1.24 watts to the 10 LEDs. Total power is 1.44 watts. Thats about a 14% loss, driver circuits could run you anywhere from 85 to 94 % efficiency based on being well matched from battery to load, so you could spend money on a good driver circuit but for that load range still wind up with the same percentage loss to the driver. Only advantage would be flatter regulation.