Led id

[Ian ParkinParticipant @ianparkin39383]

[Ian ParkinParticipant @ianparkin39383]

Can anyone identify these leds and suggest a replacement?

these are uv for a microscope i want to replace with white light

they are in a metal can withthe lens poking out the top

the body measures 4.66 mm and the can has a tag on it

from under the rim of the can to the top of the lens is 7mm

I need 20

[peak4Participant @peak4]

They look similar in size to THESE, now shown as out of stock, but the spec is there.
The download sheet points to MARL Optosource which is a UK company.

Your final choice of LEDs might come down to what driver/PSU you have fitted; some of the higher powered ones use a constant current source.
You might find that a voltage stabilised PSU for one replacement with conventional lower powered LEDs is sufficient, since you have 20 of them.
Are they all wired in parallel, or do you have a number of parallel circuits, each composed of several LEDs in series?

I'm guessing you will need to measure the voltage output from the driver under load, and also the max current supplied, and then select replacements as appropriate, bearing in mind the limits of your power supply.
Lower powered "normal" LEDs are likely to work off a constant voltage source.
Bowood Electronics might be worth contacting, and they are reasonably local.

Bill

[Ian ParkinParticipant @ianparkin39383]

Thanks bill

they are in a to18 can but i dont seem to be able to find any white in that can

[peak4Participant @peak4]

Ian, personally I've never seen any LEDs in a TO18 either; my link just came up from a Google search.
No idea of the reason for it, other than maybe filled with a thermally conductive paste to act as a heatsink.

I just used normal white LEDs when I knocked up a ring light for the camera, but when I made a moth attracting light, I used a combination of white, green, blue and UV high powered (5W) ones. These need to be mounted on a heatsink and powered from a constant current source, tailored to the LED's wattage, so a different ballgame.
Each colour has different voltage requirements, so I powered them in series pairs, each pair with their own PSU, all four PSUs wired in parallel to run off a 12v battery.

Bill

[SillyOldDufferModerator @sillyoldduffer]

Posted by peak4 on 09/03/2020 13:03:37:

… I've never seen any LEDs in a TO18 either …
No idea of the reason for it, other than maybe filled with a thermally conductive paste to act as a heatsink.

I just used normal white LEDs …

Bill

Just a guess – I suggest those Ultra-violet LEDs are shielded for safety reasons. It's to block any possibility of invisible radiation leaking sideways where it might damage an eye. Some plastics are degraded by UV, so they might still be shielded even if the LED isn't powerful enough to hurt eyes.

The precaution wouldn't be so necessary with visible light LEDs. I'd go with Bill and just use normal white LEDs.

Dave

[Michael GilliganParticipant @michaelgilligan61133]

Ian,

I have a batch of white LEDs in the traditional 5mm package

They are described as being ‘super bright’ and 11000mcd

… Drop me an eMail if you need some.

I have the spec. sheet ‘somewhere’

MichaelG.

[Ian ParkinParticipant @ianparkin39383]

Thanks for all help i have large stocks of leds but none like the ones fitted

But after a job i hate stripped out all 20 uv ones and soldered in 3mm white ones I’m in business with white light

5mm ones wouldn’t go in the shroud so i had to downsize

its off a mantis microscope so should make all the small jobs go better

vision engineering wanted an astronomical price for a white led board

[peak4Participant @peak4]

Ian, Having just read This Link, I wonder if your UV ones have built in lenses.
Assuming the replacement board also has glass lens ended white LEDs, it might explain the price of the replacement board; check out the prices on the link.

Save the UV ones; I wonder if they might be good for activating UV cure glues and resins.

Bill

[Author]

Posts