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Looking for low voltage Blue LEDs.

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Iron Hawk

Member
Joined
Jan 19, 2002
Location
Groton, CT
Do any of you know of any vendors that sell Blue leds that run on low voltages such as 2.0vdc. All I have been able to find are ones that run on 3.6-3.8vdc.
 

Arkaine23

Captain Random Senior Evil
Joined
Nov 8, 2001
leds

Those'll probably run but won't be very bright. I've got one for my power led, but I ran it off a molex with a resistor. try doing it that way, unless it's for your HDD activity or mouse or something.
 
OP
I

Iron Hawk

Member
Joined
Jan 19, 2002
Location
Groton, CT
Re: leds

Arkaine23 said:
I've got one for my power led, but I ran it off a molex with a resistor.

That is EXACTLY what i did for my power led. I moded a molex adapter for a fan with a relay and sorts to drive the 3.8v led. The leds that i am going to be replacing are in the DVD and CDRW drives.
 

Arkaine23

Captain Random Senior Evil
Joined
Nov 8, 2001
blue leds

Aren't those the smaller ones? Not 5mm? I haven't even seen small blue leds anywhere. Go red if you can't find what you want. It'd be better than green and bright enough at low voltage. Good luck finding the blues though. I know maintaining a color scheme can be very important.
 

Tbird man

Member
Joined
Jun 19, 2001
Location
Boone, NC a.k.a THE BOONIES
or if you wantes to get complex you could use a low volt solid state relay that closes at 2v to run the led from the +5v line with resisters;) well just my two hundredths of a dollar:D
 
OP
I

Iron Hawk

Member
Joined
Jan 19, 2002
Location
Groton, CT
Tbird man said:
or if you wantes to get complex you could use a low volt solid state relay that closes at 2v to run the led from the +5v line with resisters;) well just my two hundredths of a dollar:D

That is exactly what i had in mind

Tbird man said:
well the lowest voltage i could find was 3vdc (not to say they aren't out there) i thnk your best bet would be to just run the 3.8v @ 2.0v and not get the full brightness.

Same here, I just pulled out my 1728page Newark components catalog and all I could find was 5-12-24-48v as well as a few 3v and 6v relays.

I did just find some leds at UmaxPC.com that are listed as 2.5-3v.

http://umaxpc.com/store/product_info.php/products_id/168?PHPSESSID=e2db51221998b6f548facbd824f78f86

im kinda wary about ordering them becaus i bet they are realy the same thing as the 3.8v-5v that can be purchased at radioshack.
 

macklin01

Computational Oncologist / Biomathematician / Mode
Joined
Apr 3, 2002
Location
Bloomington, IN
LED voltage and wavelength

From what I've found, the color is directly tied to the wavelength:

wavelength (nm) voltage
565 (green) 2.2-3.0
590 (yellow) 2.2-3.0
615 (orange) 1.8-2.7
640 (red) 1.6-2.0
690 (another red) 2.2-3.0
880 (infrared) 2.0-2.5

etc.

I didn't find any specs on blue (and I didn't look very hard), but from what I can tell, the minimal voltage occurs in the red-orange range, then increases with decreasing (and increasing) wavelength. This is probably why you aren't seeing a large amount of variation in the voltage for the blue LED's.

-- Paul
 
OP
I

Iron Hawk

Member
Joined
Jan 19, 2002
Location
Groton, CT
yea, thats what i figured. standard blue leds are 470nm.

does any one know if the leds on UmaxPC are what they say they are? or am i going to have to risk it and find out?
 
OP
I

Iron Hawk

Member
Joined
Jan 19, 2002
Location
Groton, CT
scoobydoo said:
You could take a white one and color it blue with a magic marker, or get some of these http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=070-086 :)

I am in the same situation, I have a 3.7V Blue LED and tried hooking it up to the power LED and it was barely glowing:(

I wonder what would happen if I hooke it too the 5V? Would it handle the extra 1.3V or just blow up?

I have my power led hooked up to the 5v with a resistor, the led will prob pop if you put much more than 5v thru it, also it will start glowing a whiteish blue, and will get very hot.

What I am trying to do is attach the blue leds to the cdrom drive so they flash when the drive is reading. and for that i need a 2v led.
 

macklin01

Computational Oncologist / Biomathematician / Mode
Joined
Apr 3, 2002
Location
Bloomington, IN
Iron Hawk said:

[...]
What I am trying to do is attach the blue leds to the cdrom drive so they flash when the drive is reading. and for that i need a 2v led.

Use a small relay that switches with 2V or a transistor (NPN or PNP usually give a voltage drop of .6V or more) with a series of resistors to switch on an external circuit to power the LED. I might actually do something similar on my fanbus design. (Thanks again for the response, Iron Hawk!)

-- Paul
 

sgt. york

Registered
Joined
Apr 20, 2001
I recently did my CDroms, floppy, power and HDD leds to blue, I used the Linrose Super Brite 3mm Blue Leds. They'll work between 2v - 5v. The package doesn't have a voltage rating only .020ma. They work fine on all my devices and they're bright enough also. I got mine at Frye's Electronic the Manufacture part #4303F6. If you don't have a Frye's nearby do a search for Linrose LED's and you should get a list of some distributors who sell them. They were $2.29 at Frye's.
 

WyrmMaster

I'm a little teapot Senior
Joined
Dec 17, 2000
Location
Montana, USA
Re: found it!

FragSyndrome said:
Found it! Found a super-bright blue LED (1.7-2.2V) and the same thing in a white version, Bow before me for I am r00t.

Blue LED

White LED

can't wait to stick one of these into my cordless mouse


**bows**

I just may have to get one of those to do my TDK burner. Its got a bicolor orange / green now, and i really want blue for reading, red for burning.