I saw a few recent threads on it and i thought id post this to make the origional help file a little bit easier to understand

Materials needed:

1(or more) LED(s) (Light Emitting Diode)
Two small wires (optional)
Resistor (size varies)


LED's
-------------------

Ok, to start off with you need to know what the Specs of your LED are. If you do not knwo there is absolutly no way to know because they are not marked or identified according to wattage etc.

Some LEDs have a built in resistor and those can be plugged right into any 12v source. however those that do not have inline Resistors require a resistor.


Once you have your LED(s)

They should come with or be provided a Specifications Sheet.


Ohms Law
-------------------------

The specs are generally as followed.

Luminous Intensity= MCD:2500Typical/3000MAX
Reverse Voltage: 5.0v
DC Forward Voltage: 3.3v Typical
DC Forward Current: 20~30mA
Viewing Angle +/-10*
Lead soldering temp is generally 260*C for 5 Sec.



Now you need to learn about Ohms Law....

First i will give you Ohms Variables...

# = Number of LED's Used
led = Amps LED needs to operate or Forward current
RS = Ohms (Resistance) needed
+V = Imput Voltage
VLed = Voltage LED is rated at (Reverse Voltage)

Now ill show you Ohms law




Rs = [+V - (Vled)] / (# x led)


Or


+V - (vled)
------------ = Rs
# x led



Ohms law is used to find the resistance needed to make an electrical application work... Since we are using a RAW LED chances are the input volt used is much more then the LED can handle..


Application
--------------------

So lets say we are using this LED in a Car. The cars battery is supposed to be 12v but due to alternator current we will say that it will operate at an average of 13.45v

so lets apply our variables..


RS = ?
# = 1
led = 20~30ma so tha twill be .02~.03 so it can accept anywhere between there, so well pic .02
+V = 13.45
Vled = 5v

lets plug this into Ohms law

(13.45 - 5) / (1 x .02)

(8.45)/(.02)

422.5Ohms

So we would need one or more Resistors that can equal up to 422 or so Ohms.



Resistors
-----------------

Resistors can be wired two different ways... In a series or in parellel. i will show a description of each

- Parallel -

where you would wire the Resistor side to side similar to:

+ = Positive Wire
- = Negative wire

___+______(-)
__+_+_____(-)
_+____+___(-)
+______+__(-)
+Resistor+__(-)
+_______+__(-)
+Resistor+__(-)
+______+___(-)
_+____+____(-)
__+_+______(-)
___+_______(-)


When you wire something in a series the resistance of the Resistor is cut in half per resister you use so...

say we are using 2 resistors that are 300Ohms of resistance each wired in parallel that means we would be using 300 Ohms of resistance (300/2 = 150 each 2 resisters @ 150ohms = 300)
if we were using 3 resistors origionally rated at 300ohms wired in a series we would have 450 ohms of resistance (300/2 = 150 x 3 = 450 )

-Series-


A set of resistors wired in a Series means that the resistors are wired end to end such as :


++++RESISTOR+RESISTOR+++++++
(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)

Resistors wired in a Series ADDs their resistances to each other... so if we had two 300ohm resistors wired in parallel that means they are now 600 ohms total.. or if we had one 30ohm and one 50ohm resistor we are creating 80ohms of resistance.

note: Resistors are Dualpolor so they can be used on either Positive or Negative wires. I personally choose positive but thats me.


Multiple LED's
------------------

To wire Multiple LED's you need to firs figure out how many to use, then how you want to wire them, parallel or in a series.. the most effective way is to wirethem in Parrallel because this way if one goes out you only need to replace the one.

you use the same law of Ohms, however you change the numerator to match the number of LED's you are using (you increase the # variable)




If anyone needs any help on how to do this please feel free to ask and never hesitate. i have sucessfully made a 27 LED Lightbar for my Amp Box using this formula.






Advantages of LED's over NEON or standard lights
--------------------------------------------------------------

Unlike standard light bulbs LEDs have a very thick filiment and instead of BURNING a filiment they adjust the frequency that the filiment is charged with to direct the actual light emitted, so the lifespan of it is increased tremendously....

Unlike a NEON bar LED's require no load time or Charge time. NEONS require the particles of gas to be charged for them to operate correctly and often that can take a few seconds to at max a minute. Leds can be turned on and off instantly.

Additionally Neons are EXTREMELY fragile. LEDs are usually encased with a very thick hardplastic shell which makes them resistance to almost any impact.


Types of LED's
-----------------------
Leds come in THOUSANDS of colors, litterally. Depending on which you chose tehir wavelengths can differ indefinatly. some common colors are:

Blue
Light Blue
Dark Red
Red
Pink
Orange
Green
Purple
Tan
Yellow
Black(UV)
White
Ultra White Light

the list can go on indefinatly


I just made a LED Flashlight using 2 Ultra Bright White LED's which makes it absolutly excellent for engine work.


Good luck guys (and girls), id love to hear some stoies if ive helped.

-Nick

 

Your theory is flawed. Resistors wired in series run end-to end( - - - -)
and the resistance is added between all in the series. Parallel means they run side-to-side (| | | |) with each end being hooked to a 'common' point.

Pete

 

Its not a theory, its called Ohms law, its a law and it isnt mine..

the only reason its flawed is cause i mixed up series with parallel, and i also ****e dup my math.. 300 + 300 doesnt = 500 lol

it wa sliek 4am when i wrote this last night....

 

thanks ill probly need to know that sometime soon....very good information