Resistor for LED?
I'm going to be running a few LEDs and need to know what size resistors I need to make them work on a 12v system. Here's the LED specs:
Absolute Maximum Ratings: Reverse Voltage 5.0v D.C. Forward Current 20mA ...other info Forward Voltage @ 20mA(V): Typ: 3.5 Max: 4.5 This info can be seen at http://www.allelectronics.com/spec/LED-59.pdf Can anyone help me? Thanks! -Eric H ------------------ **1995 White Camaro Convertible 3.4 A4 Pics! *Leather & Power Everything -RK-Sport Big Block Hood & Sport Wing; Custom Racing Stripes -17x9˝" König Monsoons -Flowmaster w/ Quad 2˝" Tips -Viper Alarm, Pioneer DEH-P720, RF 800a2, Two RF He2 12" -Minnesota F-Body Club |
OHM's law states that...
V = I x R V = voltage I = current R = resistance Since the V and I are known you get... R = 12v / 20ma R = 600 ohms When the car is running that voltage figure will go up to 14v or so. R = 14v / 20ma R = 700 ohms You don't want to run the LEDs right at their current limit so use 1k ohm resistors to be safe. I = 12v / 1k I = 12ma |
Thanks man! You've always been a big help in this forum. http://web.camaross.com/bb/biggrin.gif
-Eric H ------------------ **1995 White Camaro Convertible 3.4 A4 Pics! *Leather & Power Everything -RK-Sport Big Block Hood & Sport Wing; Custom Racing Stripes -17x9˝" König Monsoons -Flowmaster w/ Quad 2˝" Tips -Viper Alarm, Pioneer DEH-P720, RF 800a2, Two RF He2 12" -Minnesota F-Body Club |
You're very welcome.
I've been doing this stuff for longer than a lot of guys on this board have been alive. If my experience can be of any help to others then great. I'm glad to help when I can. |
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