i remember back a while ago, someone posted a formula for finding the right resistor for the led to work with the 12V battery source

can someone give the formula again and perhaps tell me the resistor for this led:
Typical MCD is 620. Typical wavelength is 570nm. T 1 3/4 size (5mm). Clear lens color. Viewing angle of 12°. 30 mA current max. Typical voltage 2.1V, with a maximum of 2.8V. Package of 1.

tia



WTB----- Dodge Omni: condigion i don't care, clean title needed

mods:
star stage III clutch
gutted cat-cherry bomb-banzi muffler(thanks kris)
cai(thanks kris)
f/r upper tie bars
hotter NGK plugs
platnum plus window tint
all black interior
5 color indiglo gauges (thanks kyle)
stock RS rims painted black w/neon green calipers and drums (thanks kris)
altezas

stereo equipment:
old sony X'PLOD head unit
300 watt amp kit
120 watt sks power pro cheapo amp
12" kenwood wave in a custom wrapped box

future mods(in no particular order):
engine rebuild/2.4 swap
turbo.....
lower it
wheels
seats
exhaust
piant job
turbo wing
hood
body kit
neons all around
projectors
custom tail lights
better stereo equipment

its ohms law, do a search on the net and you will find calculators on it, but what are you useing it for? 620mcd is not very bright? For the HVAC the mcd is 1500+

i used to have that formla on my comp, but lost it. You should be able to search the web for it though. btw.. if you plan on using that led to replace a standard light/bulb it will not be bringht enough.. you need somehting like 1000+mcd.

i can't find a green led that bright....

do ya'll know where i can get like 10 or so bright green leds?

thanks



WTB----- Dodge Omni: condigion i don't care, clean title needed

mods:
star stage III clutch
gutted cat-cherry bomb-banzi muffler(thanks kris)
cai(thanks kris)
f/r upper tie bars
hotter NGK plugs
platnum plus window tint
all black interior
5 color indiglo gauges (thanks kyle)
stock RS rims painted black w/neon green calipers and drums (thanks kris)
altezas

stereo equipment:
old sony X'PLOD head unit
300 watt amp kit
120 watt sks power pro cheapo amp
12" kenwood wave in a custom wrapped box

future mods(in no particular order):
engine rebuild/2.4 swap
turbo.....
lower it
wheels
seats
exhaust
piant job
turbo wing
hood
body kit
neons all around
projectors
custom tail lights
better stereo equipment

check out eled.com

OHMS LAW

E/I*R Or said E over I times R

E=Power (I Think)
I=Current
R=Resistance

I just posted this on another thread about hooking up LEDs

You'll need a ressitor otherwise you'll burn it out. Most LED are rated for about 5V.
To figure out what resistor you need use this formula:

(Vcar-Vled)/Aled = R

Vcar is the Voltage of the car, assume 14V to me on the safe side.

Vled is the Voltage the led is rated to (you'll find it on the package)

Aled is the current rating in Amps of the LED (also on the package and remmember 1mA =.001A)

R is the resistor you'll need in Ohms. You won't find a perfect match so use the resistor that's closest.

Keep in mind that the bigger the resistor the dimmer the LED will be, but you use to small of a resistor you could burn it out.