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[Bighomedog11]

Hey I need to know what resistor do i need for 10 3mm Blue LEDs? I am going to hook them up to my jewel so i am wondering what resistor i will need? I dont understand the resistor calculator because i dont have the specs. of my LEDs.

[Lung-Dart]

Where did you get your LED's from? The site should contain a data sheet with the specs on it. The resistor formula goes like this.

R = Vs-Vf / If

R = Resistance in ohms
Vs = Voltage source in volts
Vf = Forward voltage rating of the LED, in volts
If = Forward current rating of the LED, in Amps

Normally an LED has roughly a 2v forward voltage/voltage drop, and is brightest around 20mA.

So for a 5v supply
R = 5V -2V / .02A, R is around 150 ohms. Anything in this range will work fine (doesnt have to be right on the money.)

12v supply
R = 12V - 2V / .02A, R is around 500 ohms. again a 470ohm here will do the trick.

The reason why this is done is because LED's are Diodes. Diodes need a certain voltage to turn on. Once they are on, they do not receive any more voltage. The rest of the voltage will go across the resistor you put in series with it. If you do not do this, the current will be decided by the resistance of the wire, which is really small and will cause a lot of current flow. So we pick a sane resistor to eat up the rest of the volts the LED is not using. Then we use Ohms law, to decided the resistance value. If you need any info on ohms law, Wikipedia/google is a good starting point. It is a very basic principle and easy to understand, so you wont need to rack your brain to figure it out, which is nice sometimes for a change.

[Bighomedog11]

QUOTE(Bloodfin @ May 23 2008, 12:50 PM)

If you dont have the specs of the LEDs how can we help you?

Voltage norm 3.0V - max 3.3V
100 Ohm resistor for 5volt supply
470 Ohm resistor for 12volt supply

I dont know, I thought you guys might of known. But anyways i am going to wire them all up 2gether. Can I use only 1 resistor for all the LEDs wire 2gether? Its going to be 10 3mm Blue Leds. Is 10 LED's to many for the pringle lid mod well Jewel.

Edit:
I got them from some guy not sure whats his name on here but he used to sell stuff his AIM is..mikes805mods

I have some 100 and 330 ohm resistor,so will that work?

[Lung-Dart]

QUOTE(Bighomedog11 @ May 23 2008, 05:57 PM)

I dont know, I thought you guys might of known. But anyways i am going to wire them all up 2gether. Can I use only 1 resistor for all the LEDs wire 2gether? Its going to be 10 3mm Blue Leds. Is 10 LED's to many for the pringle lid mod well Jewel.

Edit:
I got them from some guy not sure whats his name on here but he used to sell stuff his AIM is..mikes805mods

I have some 100 and 330 ohm resistor,so will that work?

The best thing about doing this mod is getting to eat pringles.

Wire all the LED's in parallel. This will let you get away with one resistor, But the value is going to change. Using the same estimates that I gave above, Vf = 2V, If = 20mA

10 in parallel would take 200mA (10x 20mA)

5v supply:
R = 5V - 2V / 0.2A, R = 15 ohm

12v Supply
R = 12V - 2V / 0.2A, R = 50ohm

The good news here is two 100ohm resisters in paralell will equal 50ohms.

So it would go something like this

CODE

                                  12v
                    ________|__________
                   |                                        |
            100ohm                            100ohm
                  |__________________ |
                                       |
_________________|____________________
 |         |        |        |         |        |        |       |        |        |
LED LED LED LED LED LED LED LED LED LED
 |____|____|___|____|___|____|___|____|___|__
                                      |
                                    GND

Then arrange the LED's in a circle around the pringles top. Word of advice, people who say "no" as a reply usually are useless. They have all the time in the world to troll around forums, but not enough time to look into helping you. Ignore them forever.

EDIT: fixed shitty ASCII art

[Bighomedog11]

QUOTE(Lung-Dart @ May 23 2008, 01:25 PM)

The best thing about doing this mod is getting to eat pringles.

Wire all the LED's in parallel. This will let you get away with one resistor, But the value is going to change. Using the same estimates that I gave above, Vf = 2V, If = 20mA

10 in parallel would take 200mA (10x 20mA)

5v supply:
R = 5V - 2V / 0.2A, R = 15 ohm

12v Supply
R = 12V - 2V / 0.2A, R = 50ohm

The good news here is two 100ohm resisters in paralell will equal 50ohms.

So it would go something like this

CODE

                                  12v
                    ________|__________
                   |                                        |
            100ohm                            100ohm
                  |__________________ |
                                       |
_________________|____________________
 |         |        |        |         |        |        |       |        |        |
LED LED LED LED LED LED LED LED LED LED
 |____|____|___|____|___|____|___|____|___|__
                                      |
                                    GND

Then arrange the LED's in a circle around the pringles top. Word of advice, people who say "no" as a reply usually are useless. They have all the time in the world to troll around forums, but not enough time to look into helping you. Ignore them forever.

EDIT: fixed shitty ASCII art

yAH I know i just ingore people like that. That say dum stuff in my post.. But thanks for all your help you are GREAT!! But i am a big noob at this and want the best out of it i can get. Can i use 2 100ohm resistors and have all 10 leds connecting to one each other. Like this i will draw a digram and tell me if its correct. The red is the resistor and the black is the LED.

[Lung-Dart]

QUOTE(Bloodfin @ May 23 2008, 06:31 PM)

Thanks Lungtard.

You summed it up for me.

I don't Troll though.

I was actually looking it up a hit the send button. I was hopeing on editing it in.

A mistake I made by accident.

I doubt your comment was something of the same.

Word of advice, don't listen to people who have pointless things to say about others. Jump to conclusions much?
They may know whats going on but are obviously just whiners.

Ahhh flames. Good times good times.

Bighomedog11: Your drawing makes no sense to me at all. Sorry.

Ill do up a drawing in the gIMP, and see if it helps.

EDIT: Circuit



No if there was anything to ever flame, that my friends, is it.

[Bighomedog11]

Sorry about it i did it fast in paint.. Here a better one.. So will 2 100 ohm resistor work with 10 3mm Leds?

[Lung-Dart]

Ahhh, the circuit you drew is a series circuit. One thing, then another, etc. The circuit you need to do is parallel. Everything coming from one line. so it goes 12v, two resistors in parallel, 10 LED's in parallel

Also drawn in the (almost) shape of an xbox jewel for your convenience.

[Bighomedog11]

QUOTE(Lung-Dart @ May 23 2008, 01:58 PM)

Ahhh, the circuit you drew is a series circuit. One thing, then another, etc. The circuit you need to do is parallel. Everything coming from one line. so it goes 12v, two resistors in parallel, 10 LED's in parallel

Also drawn in the (almost) shape of an xbox jewel for your convenience.

O alright so i need to do a parallel for the pringle lid mod. Can u draw me a digram on how to do it? So the 2 100 ohm resistor will work fine?

[SICKdimension]

I've made it as simple as possible:
http://resistorcalc.sickmods.net/

All you have to do is type in 10 and you'll see that you should use a 10 ohm 1 watt resistor, and wire in parallel to 5V.

[Bighomedog11]

QUOTE(SICKdimension @ May 23 2008, 10:01 PM)

I've made it as simple as possible:
http://resistorcalc.sickmods.net/

All you have to do is type in 10 and you'll see that you should use a 10 ohm 1 watt resistor, and wire in parallel to 5V.

Thanks, I was lookening for you site to use the calculator. But will 100 ohm resistors work? Because i have some of those laying on my bed.. But i dont have no 10 ohm resistors

[SICKdimension]

Sure. Enter 1 in the box and you'll see that a 100 ohm resistor works for 1 LED to 5V. So, use 1 resistor per LED to 5V.