making your own leds
Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=108852
Printed Date: May 05, 2024 at 4:58 PM
Topic: making your own leds
Posted By: burgies
Subject: making your own leds
Date Posted: November 11, 2008 at 11:16 PM
So far in my car i have modified kits to be able to control them all through a switch and have them powered from the back of my cig lighter, however now i want to have some glow coming from in my AC vents :P only problem is it only requires 1 LED. I dont actually know anything about putting these things together myself, however i can wire it into my existing system, so basically im asking how do you put together your own LED with what ever resistors you need so that it can be powered via 12 volts.
thanks!
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-Burgies
Replies:
Posted By: KPierson
Date Posted: November 12, 2008 at 5:43 AM
The best way to go about this would be to figure out the forward current of the LED. Then use Ohm's law and determine the correct resistor (assume a battery voltage of 14.5 or so). Ohm's Law is Resistance = Voltage / current. Once you have the minimum resistance you can install a 10K pot inline with the resistor. Wire the LED up with your current LEDs (positive and negative). Turn the LEDs on and then use the pot to dial in the brightness you want. Once you have the brightness you are happy with you can either leave the pot in our measure the resistance of it and replace the pot with a fixed value resistor. ------------- Kevin Pierson
Posted By: bigjohnny
Date Posted: November 20, 2008 at 6:32 AM
or just use the proper resistor..... figure it out using an led calculator somewhere on the net, there are lots.
Posted By: b1b2b3
Date Posted: November 21, 2008 at 8:03 AM
would also suggest checking the power dissipation(1/4W, 1/2W etc.) of the resistor. The resistor will need to be able to block all the current without getting too hot.
A good way to figure out anything to do with LED's and circuits is to use this website:
https://led.linear1.org/led.wiz
it's absolutely brilliant :).
Posted By: KPierson
Date Posted: November 21, 2008 at 9:08 AM
bigjohnny wrote:
or just use the proper resistor..... figure it out using an led calculator somewhere on the net, there are lots.
Simply using the proper resistor won't always give you the best results, especially when you're trying to achiece a certain effect. I recently did a project that involved 9 small 24DC LEDs in a home application. I calculated the "proper" resistor value and installed everything. When the LEDs were on they were WAY too bright. I played around with the resistor value and ended up using a resistor that was a fraction of the "correct" value to achieve the desired result. ------------- Kevin Pierson
Posted By: bigjohnny
Date Posted: November 23, 2008 at 9:04 AM
KPierson wrote:
bigjohnny wrote:
or just use the proper resistor..... figure it out using an led calculator somewhere on the net, there are lots.
Simply using the proper resistor won't always give you the best results, especially when you're trying to achiece a certain effect.
I recently did a project that involved 9 small 24DC LEDs in a home application. I calculated the "proper" resistor value and installed everything.
When the LEDs were on they were WAY too bright. I played around with the resistor value and ended up using a resistor that was a fraction of the "correct" value to achieve the desired result.
true, i was just saying if all he was doing was putting together an led to run on his car voltage, then he just needs to use the proper resistor. this will run the light as brightly as intended by the manufacturer.
Naturally if you want it dimmer or brighter you would have to make the proper adjustments.
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