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what resistor to dim 12v led bar

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=116473
Printed Date: June 11, 2024 at 5:24 PM


Topic: what resistor to dim 12v led bar

Posted By: zeddy
Subject: what resistor to dim 12v led bar
Date Posted: September 21, 2009 at 6:34 PM

Sorry guys I am a little rusty
I have a 12v led bar(it has 8 led's in it)
It is meant for offroad lighting, the problem is it's too bright,
I would like to use a resistor to dim the led bar.
It draws 1.03 amps and uses 12volts and 12.4watts.
It is suppose to be fully dimmable so I would like to figure out a way to make a 1/2 power and 3/4 power position.
Does the resistor go in series or parralel with the load?

It is quite an impressive light it is from https://www.rigidindustries.com/product_p/rgdl04.htm if anyone is interested in checking them out.

I have a big one on my truck
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Replies:

Posted By: i am an idiot
Date Posted: September 22, 2009 at 6:14 AM

The resistor needs to go in series with the load.  You are going to have to drop the voltage a lot to get them to dim even a little.  Do you have an electronic parts retailer near you?  If so, Have the wires accessible when you drive there, purchase a package of 1K ohm 2 watt resistors.  Wire the resistor in series and see if it dims the unit to your liking.  if it does not, wire the second 1K resistor in series also, test again.  If the 1K resistor makes it too dim, parallel the second 1K resistor with the first one to give you a 500 ohm load, turn them on and test again. you will now know how bright they are with 1K, 2K and 500 ohms worth of resistance.  You should at least have a better idea of what values to try next. 

The resistors come 2 per pack and sell for 1.00 in the U.S.


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