Can anyone identify this emitter?

deathless · January 14, 2015, 3:49am

unknown00101 · January 14, 2015, 4:13am

Looks like an MKR.

wight · January 14, 2015, 4:31am

I’m curious where you ran into a loose MK-R? It could be either 6v or 12v, they come in both varieties.

deathless · January 14, 2015, 4:51am

My friends were working on a projects, and bought a couple of hundred of these and had a few left over so I ended up taking them.
I think these are the 12V variety. What can I do with them?

wight · January 14, 2015, 4:57am

Not a lot, I suspect. What do you want to do with them? For flashlight use 12v is pretty prohibitive. How many do you have?

deathless · January 14, 2015, 5:35am

[/quote]
Not a lot, I suspect. What do you want to do with them? For flashlight use 12v is pretty prohibitive. How many do you have?
[/quote]

I have 3 to 5 of them around the house. I only got them because they’d be tossed otherwise. What’s the easiest way to check their forward voltage? What’s a good resistor value to use? If you want I can send you one at no charge.

wight · January 14, 2015, 5:49am

I’ll take dibs on one, but first let’s make sure that you don’t want to do a project with all of them!

There may be identifying marks for the voltage, but I don’t know them. I’d say that the best way to test the voltage is to use 4 or 5 NiMH AA cells and see what happens when you briefly touch the leads to the pads. If it doesn’t light up you’ve probably got the 12v variety… try 3 fully charged li-ion cells in series at that point. If it still doesn’t light up, you’re doing it wrong.

Driving these with a limiting resistor is a just plain bad idea IMO. I recommend that you do not attempt it. Instead use a CC/CV PSU. You can get those really cheaply. You’ll also need some MCPCB to mount the things on, that could get expensive considering that MK-R are available pre-mounted in the $4-5/ea range…

If you had an 18-19v laptop PSU you could run as many 12v emitters as you wanted in parallel using a buck PSU of appropriate amperage… maybe something like this: http://www.ebay.com/itm/DC-8A-Buck-Converter-Step-Down-Regulator-CV-CC-7-40v-12v-to-1-25-36V-5v-LED-Driv-/261304256176

A little fishing will also find you a boost PSU with enough voltage and current to run 2s2p with the 12v emitters.

deathless · January 14, 2015, 6:07am

wight:

I’ll take dibs on one, but first let’s make sure that you don’t want to do a project with all of them!

There may be identifying marks for the voltage, but I don’t know them. I’d say that the best way to test the voltage is to use 4 or 5 NiMH AA cells and see what happens when you briefly touch the leads to the pads. If it doesn’t light up you’ve probably got the 12v variety… try 3 fully charged li-ion cells in series at that point. If it still doesn’t light up, you’re doing it wrong.

Driving these with a limiting resistor is a just plain bad idea IMO. I recommend that you do not attempt it. Instead use a CC/CV PSU. You can get those really cheaply. You’ll also need some MCPCB to mount the things on, that could get expensive considering that MK-R are available pre-mounted in the $4-5/ea range…

If you had an 18-19v laptop PSU you could run as many 12v emitters as you wanted in parallel using a buck PSU of appropriate amperage… maybe something like this: http://www.ebay.com/itm/DC-8A-Buck-Converter-Step-Down-Regulator-CV-CC-7-40v-12v-to-1-25-36V-5v-LED-Driv-/261304256176

A little fishing will also find you a boost PSU with enough voltage and current to run 2s2p with the 12v emitters.

I definitely won’t need all of them, school is starting back up this week so I won’t have time to start any projects for a while. You can PM me your address if you like.