12-LED 390nm UV

12-LED 390nm UV LED Flashlight, retail $19.99 (http://store.advancedmart.com...)
Manufactured by (Unknown) for Advancedmart (www.AdvancedMart.com)
Last updated 11-26-08

This unnamed flashlight is an aluminum-bodied light that has 12 UVA (advertised as 390nm) LEDs in the end, powered by two AA cells in the barrel.

Because it is powered by two AA cells, there is a DC-DC inverter inside to boost the 3 volts from the battery to the 3.6 to 4.0 volts the LEDs need.


Getting this light to work is as easy as firmly pressing then releasing the button on the back of the tailcap.

Repeat the same action to turn the light off.

The switch has a long throw ("action") to it; you have to be certain to press it all the way down until it clicks & then release it to make it function.

To change the batteries in this flashlight, unscrew and remove the tailcap, dash it to the floor, look at it all funny, cock your head like a puppy that doesn't understand what it had just been told, and stomp on it with the heels of old or used baseball shoes...O WAIT!!! YOU'LL NEED THAT!!! So just set it aside instead.

Tip the open end of the barrel into your hand, and dispose of or recycle as you see fit the used AA cells that come out.

Slide two new AA cells into the barrel, button-end (+) positive first, and screw the tailcap back on.
Aren't you glad you didn't stomp on that tailcap now?

Measures 593mA on my DMM's 4A scale.

I beat the living tweedle out of it (gave it ten firm whacks against the concrete floor of a patio; five whacks against the side of the tailcap and five whacks against the side of the bezel), and found the expected damage. There is some VERY minor gouging to the bare Metalbeezelmon - er - the bare Metalguardramon - o wait, he's already metal - the bare Metalmarineangemon - um that's not it either...the bare Metalgallantmon...er...uh...wait a sec here...THE BARE METAL (guess I've been watching too much Digimon again! Now I'm just making {vulgar term for feces} up here. ) on the sides of the tailcap and bezel where it was struck. No optical or electrical malfunctions were detected. It still works as well now as it did when I received it a little while ago today.

It flickered when I was administering that last test, but I sat here and shook the urine out of it and it functioned properly. Like I just said, no optical or electrical malfunctions were detected.

This flashlight is splash- and weather-resistant at absolute maximum, but it is not submersible. It failed "The Suction Test" rather miserably. So please try not to drop it in creeks, rivers, ponds, lakes, oceansides, docksides, puddles of white rat pee, slush piles, mud puddles, tubs, toilet bowls, cisterns, sinks, fishtanks, dog water dishes, or other places where water or water-like liquids might be found. A little rain or snow probably wouldn't hurt it though, so you need not be too concerned about using it in lightly bad weather.

If it fell in water and you suspect it got flooded, disassemble it as you would for a battery change, unscrew and remove the bezel (head) and tailcap, dump the water out of the barrel and bezel if necessary, and set the parts in a warm dry place for a day or so just to be sure it's completely dry inside before you reassemble and use it again.

If it fell into seawater or if somebody or something peed on it, douche all the parts out with fresh water before setting them out to dry. You don't want your flashlight to smell like seashells or urine when you go to use it next. Besides, salt (from seawater or pee) can't be very good for the insides.

There is some longitudinal fluting on the bezel, barrel, and and tailcap, so retention (the ability to hold onto the flashlight when your hands are cold, wet, or oily) shouldn't be much of an issue.

Some battery rattle is evident when the unit is shaken.

The peak wavelength advertised is 390nm; this was spectrographically measured at approximately 393nm; while this wavelength is just a little longer than advertised, this is still well within spec.

I must emphasize, protect your eyeballs when using this light. You only get one set of eyes - and if you wreck them, you can't just go down to the local seven-eleven and buy a can of them.
Here is one simple way you can do this:

Most sunglasses and some prescription eyeglasses have some degree of UV protection already; to determine if yours do or not, aim the flashlight at something that clearly fluoresces (such as those neon green & orange stickers that occasionally show up on your mail, day-glow orange price tags, or painted portions of a blacklight poster), positioning the light so the object in front of it glows (fluoresces) brightly from the ultraviolet light. Then put the glasses between the face of the light and the target. If the glow stops or dims dramatically, the glasses are stopping the UV and you can use them as eye protection at least for short-term use.
However, if the glow remains or dims only slightly, look for another pair.

In any case, never look directly at the LEDs without eye protection - not even for a minute.

Symptoms of UV exposure may not appear immediately; they can be delayed by 30 minutes to several hours. They can include a burning or "sand in the eyes" sensation, and a hazy look around light bulbs and other bright objects. Mild cases are self-correcting within 24 to 36 hours; however if despite my warnings you still stared at this light from close range for more than a few minutes, it might not be a bad idea to see an eye doctor and tell him you've been exposed to UVA radiation.

DISCLAIMER: I shall not be held responsible for any damage or loss of eyesight arising from your use or misuse of the information on this page. Thank you for listening.

The flashlight has a label on it with the following text:

Ultra Violet (UV) Light
Visible and Invisible
LED radiation can
damage your eyes.
Do not stare at the LED
light or reflected UV light
Keep away from children

I do not have the necessary instrumentation to measure the output power of an array of UV LEDs like this (the front of this light far exceeds the size of the sensors at my disposal that might be appropriate for the wavelength involved), but I'd "guesstimate" the total radiated output power at between 12mW and 18mW (1-1.5mW per LED).

The LEDs have their bond wires ("whiskers") attached at their flat sides, not their corners. So I know for a fact that Nichia does not make them. I do not know who does, so please stop asking.

Beam photograph on the test target at 12".
There was some fluorescence from the target, but it was rather minor.
Wavelength is too short for me to measure intensity.

The security strip in a US $20 bill fluorescing.

Security features in an ID card and a Visa debit card fluorescing.

Screwdrivers used for the photograph directly below.

Screwdriver handles fluorescing under the radiation produced by this light.

Plastic hummingbird from a set of Hummingbird Wind Chimes glowing.
The hummingbird shown is the transparent light blue one.

Spectrographic plot
Spectrographic analysis of the LEDs in this flashlight.

Spectrographic plot
Same as above; spectrometer's response band limited to a range of 350nm to 430nm. USB2000 spectrometer graciously donated by P.L.

Test unit was sent by J.W. of AdvancedMart on 10-31-06, and was received on the afternoon of 11-02-06.

UPDATE: 00-00-00

Wavelength is close to the wavelength advertised
Uses batteries that are common & relatively inexpensive

Not waterproof or submersible

    PRODUCT TYPE: UVA LED Flashlight
    LAMP TYPE: 5mm LED
    No. OF LAMPS: 12
    BEAM TYPE: Medium spot w/dim corona
    SWITCH TYPE: Twist bezel on/off
    BEZEL: Metal; LEDs inset into hosels for them
    BATTERY: 2xAA cells
    WATER RESISTANT: Light splatter-resistance at maximum
    ACCESSORIES: 2xAA cells, short lanyard
    WARRANTY: 90 days


    Star Rating

12-LED 390nm UV LED Flashlight * http://store.advancedmart.com...

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