series LEDs + ?Resistor
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=54752
Printed Date: June 07, 2024 at 3:43 AM
Topic: series LEDs + ?Resistor
Posted By: jappee
Subject: series LEDs + ?Resistor
Date Posted: April 27, 2005 at 9:32 PM
Hi all,
I hope you can help with a quick ,yet almost stupid question. If I have 12 LEDs in series with a 460 ohm resistor the voltage requiRED / expected is...???? And if I was to use a 110v source, the required resistor value is..???
Any help appreciated, It's just a little confusing to figure the resistance/voltage drop across all of the LEDs vs. just one. There are actually five parallel banks of 12 LEDs in series. These form RENAULT through holes in plastic sheet. Also I know that 12v doesn't work and that 110v lets you enjoy them for about 1-2 seconds, then...
TIA
jappee
Replies:
Posted By: ff-mike
Date Posted: May 24, 2005 at 12:50 PM
You need only be concerned with voltage drop, as in theory there is no set resistance. 12 LEDs will drop about 8.5 volts, and the source is 12V. That leaves 3.5 volts. Our current should be set at 25 mA, which gives a resistance of 140 ohms. The 480 is limiting you to about 8mA For 110v, you would want 4000 ohms, and LEDs that have a PIV of 110v
Posted By: Scuba_04
Date Posted: June 12, 2005 at 12:46 AM
OHM's Law!!!!!!!!!!!!!!!!!!
-------------
Steve
Music Mart
Installer
|