LED Help

[pro-rider46]

does anyone know much about leds. i accendently broke two. i just wanted to see them work, so i touched them to a 9v battery, and the went dull real quick, i know now i should have done that, so how do i put power to these, with out buring them up. the package says 3.7 volt - 20mA - 2600mcd, so any help is appreciated, thanks in advance.

[MOFO]

You need to delivery the exact amount of power/voltage spec'd out by the LED. As you already found out, if you do not do this, it burns out.

You will need a simple circuit to cut down or modify the power to match the LED. A simple resistor can help you do this...

What exactly are you trying to do?

[wilkin250r]

That's odd, that doesn't sound right at all, unless they are resistor-type LED. 3.7V is really odd, they should be only about 1.2V.

But it can easily be done. I can tell you everything you ever want to know about LED lights. Heck, I can even tell you the molecular makeup and specific energy gaps that give off the light. I can bore you to tears on the subject.

In order to power them with a 9V battery, you will need some resistors. If you REALLY want to play around with them, and you're willing to go buy yourself some resistors, I can walk you through the whole thing. (they're only about 5-10 cents each, so $1 can get you an assortment of various values)

[MOFO]

Originally posted by wilkin250r
That's odd, that doesn't sound right at all, unless they are resistor-type LED. 3.7V is really odd, they should be only about 1.2V.

But it can easily be done. I can tell you everything you ever want to know about LED lights. Heck, I can even tell you the molecular makeup and specific energy gaps that give off the light. I can bore you to tears on the subject.

In order to power them with a 9V battery, you will need some resistors. If you REALLY want to play around with them, and you're willing to go buy yourself some resistors, I can walk you through the whole thing. (they're only about 5-10 cents each, so $1 can get you an assortment of various values)

Really? I seem to remember seeing LED's that run from various voltages...(without an inline resistor).

[pro-rider46]

thanks for the responses guys, well, i was going to use these for a brake light on my 450r. i broke my stock led brake light, and i dont feel like buying a 80 dollar thing, that i can break again, the leds are more low profile then the whole light. i was just seeing what the color shade was, and if there bright enough, well if going to have to start up my quad and see what the voltage is on the thing, then i will buy some resistors and play with that some, and maybe i can figure this out, does this sound good with you guys.

[pro-rider46]

http://www.radioshack.com/product/index.jsp?productId=2102851&cp=&parentPage=search

this is the led i was using

[ricksmx865]

get the 330 ohm resistors..... they work ive done it before

[pro-rider46]

what have you done before?

[wilkin250r]

Originally posted by MOFO
Really? I seem to remember seeing LED's that run from various voltages...(without an inline resistor).

I admit it, I'm partially wrong in this case. In fact, mostly wrong.

You are correct, LED lights do come in various voltages, usually corresponding to different colors. Orange and yellow are about 2V, greens are slightly higher, while red is slightly lower. From memory, I couldn't remember if it was 1.2V or 1.7V (red). I didn't bother to look it up, I had a 50/50 chance and I chose wrong. But I certainly knew that it wasn't 3.7V

A little web searching refreshed my memory, AND taught me something new. Apparently the new generation of high-output LED lights have a significantly higher voltage drop. 3.7 volts is entirely likely.

[wilkin250r]

But this project sounds interesting. You'll have to do a little bit of math, using Ohms Law. I can help.

Right off the bat, I can tell you that your quad is a 12V system, but the actual voltage is probably a little closer to 13.5V.

So, tell me, do you want to experiment with the 9V battery, or directly on your quad? To get maximum brightness, the 9V battery should use a 270 ohm resistor, the quad is slightly higher voltage, so it needs slightly higher resistance of 500 ohms.

The LED will only light up when hooked in a certain direction (don't worry, hooking it up backwards won't hurt it, it just won't light). But the resistor can go anywhere, it doesn't matter which side it's on.


I'm an electrical engineer, I can help you hook up any configuration of LED lights you want. We can connect multiple LED's in different configurations to get more light output.

[Dan_Guetter]

I think we first need to understand the history of LED. In the early 20th century, Henry Round of Marconi Labs first noted that a semiconductor junction would produce light. Russian Oleg Vladimirovich Losev independently created the first LED in the mid 1920s; his research, though distributed in Russian, German and British scientific journals, was ignored. Rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide (GaAs) and other semiconductor alloys in 1955. Experimenters at Texas Instruments, Bob Biard and Gary Pittman, found in 1961 that gallium arsenide gave off infrared (invisible) light when electric current was applied. Biard and Pittman were able to establish the priority of their work and received the patent for the infrared light-emitting diode. Nick Holonyak Jr., then of the General Electric Company and later with the University of Illinois at Urbana-Champaign, developed the first practical visible-spectrum LED in 1962 and is seen as the "father of the light-emitting diode". Holonyak's former graduate student, M. George Craford, invented in 1972 the first yellow LED and 10x brighter red and red-orange LEDs.

Shuji Nakamura of Nichia of Japan demonstrated the first high-brightness blue LED based on InGaN, borrowing on critical developments in GaN nucleation on sapphire substrates and the demonstration of p-type doping of GaN which were developed by I. Akasaki and H. Amano in Nagoya. The existence of the blue LED led quickly to the first white LED, which employed a Y3Al5O12:Ce, or "YAG", phosphor coating to mix yellow (down-converted) light with blue to produce light that appears white. Nakamura was awarded the 2006 Millennium Technology Prize for his invention.
What is a LED you say? A light-emitting diode (LED) is a semiconductor diode that emits incoherent narrow-spectrum light when electrically biased in the forward direction of the p-n junction. This effect is a form of electroluminescence.

An LED is usually a small area source, often with extra optics added to the chip that shapes its radiation pattern. The color of the emitted light depends on the composition and condition of the semiconducting material used, and can be infrared, visible, or near-ultraviolet. An LED can be used as a regular household light source.

[wilkin250r]

Originally posted by Shift_DVS
I think we first need to understand the history of LED. In the early 20th century

Oh, stop it. You're killing me... :rolleyes:

[MOFO]

Originally posted by wilkin250r
Oh, stop it. You're killing me... :rolleyes:

LOL :D

[pro-rider46]

sorry i havent said much in the past 2 days, i had a party, then helped a friend drag race his yfz. but anyways, i have found some leds on ebay, they are a 50 piece set of blue thats intesity is 13000mcd, and are prewired with six inches of wire and resistors built right in. ideal for 9v-12v. and about 11 dollars that includes shipping. so i might just buy those, and play around, haha.:D

[pro-rider46]

also out of curiousity, the 450r's brake light is already led, could it maybe have resistors inline before the brake light, i dont think it would but, i should probably just hook it up to a ohm meter and see what the voltage is.

[wilkin250r]

LED lights are obviously different than standard light bulbs. With very little exception, any LED fixture is going to have some sort of resistor in it.

Why do you need to replace your brakelight? Did it blow out, or did it get broken in some way. Do you think it might be fixable?

[pro-rider46]

well. it was a wheelie victim, they are already led, and are expensive, 80 bucks i think for a brand new one from honda. i didnt have one for a while, and i just zip tied the plug and wire going to the light up out of the way, well i was having sputtering problems with my quad and they were just to lazy to zip tie it back up. and the plug on the wire, made friends with my chain and bit the head off of the wire, so now its just wire, and im just goin to play around with some of the leds i bought of ebay.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&sspagename=ADME%3AB%3AEOIBSAA%3AUS%3A11&viewitem=&item=320170402540

thats the link for the leds that i bought, notice that they are 45000 mcd on average, and 60000 mcd on max, they are already to put on, with wire, and resistors, i was going to get some resistors and do it myself, but i hate soldering, cause im not real good, and my dad doesnt really have time for my crap. and if i had 50 of them things to solder, it would kinda suck.