Connecting LEDs to molex connector part 2

[goodgod]

I'm going to wire and solder 5 super bright LEDs in series with a 100 ohm resistor, and i'm going to use the +12v on a molex connector. My question is... What if I plug that molex connector in a molex to 3pin splitter to my fan controller, will it work?

LEDs, resistors and the molex connector

Some black and yellow wires

The 4 pin molex to 3 pin splitter

Here's a drawing on how the wires are connected in the splitter:

My entire LED setup

That's the comparison between a standard connection on a male molex and the splitter i'll be using. If i plug the yellow and black wires at the same place i would plug them on a standard molex, the 12v would go in the red wire on the 3pin fan...is it the 5v? My question is....where do I plug the yellow and black wires so that the 12v and ground will be at the right place in the fan controller?

 

[Skeith]

Yeah it will work, You did find out the drop voltage for the leds with Ohms law right?

 

[goodgod]

yeah i did, u told me to do so

I'll do this setup and plug the yellow at the far left and the black just next to it, i'll tell you if it works and post pics

Thanks!

 

[four4875]

fans are goofy lol. on a normal 3 pin fan, the red is +12v, black ground, and yellow is the tachometer signal wire, which pulses ground.

 

[goodgod]

ok! now it's clear! Thanks alot!

IT'S ALIVE!

The setup is working perfectly!

I'm posting pics soon!

 

[kbtat2]

I need to read up on this more. I've been wanting to install some blue leds into the clear plexiglass mounting bracket on my DangerDen Maze 4 thats on my video card.

 

[SolidxSnake]

I need to read up on this more. I've been wanting to install some blue leds into the clear plexiglass mounting bracket on my DangerDen Maze 4 thats on my video card.

It's not really that hard. Drill a hole for the LED in the plexiglass, put in the LEDs, then glue them in. then solder them in series. the power source goes to the positive lead of the first LED, and the ground goes to the negative lead of the last LED. then just solder positive->negative for each LED (1st led's negative to 2nd led's positive etc). find a calculator, find the voltage and mA rating of the LEDs, then find out the voltage source you'll be using, and it spits out the resistor rating you'll need. solder that to the positive wire, then somehow connect that to your power source. very very simple.

 

[Skeith]

I need to read up on this more. I've been wanting to install some blue leds into the clear plexiglass mounting bracket on my DangerDen Maze 4 thats on my video card.

Its simple you just need to know the forward voltage drop on the LED.
2.2v @ 22ma is typical.

So if you were to install 1 LED with a 2.2v forward drop and a forward current of 22ma you would use the Ohms law formula as follows.

R=E/I (where R=resistance in ohms : E=Voltage differance in volts : and I=Current in amps.

so one 2.2v LED on the 12v rail would result in a volatage diff of 9.8v
and 22ma is equal to .022Amps

So plugging them into the formula you get
R=E/I
R=9.8/.022
R=445.45 ohms
So a 450Ohm resistor would do.

If you want to add more than one LED you connect them in serise. This results in the drop voltage being a multiple of the number of LED you decide to connect, and the current stays the same.

so for 3 LEDs in a serise with a drop of 2.2v @ 22ma you would find that the dropp voltage is equal to 12-(2.2*3)=5.4v
The current is the same so 22ma = .022Amps

And the formula is used exactly the same as before.

R=E/I
R=5.4/.022
R=245.45Ohms
So a 250 Ohm resistor would be fine.

 

[kbtat2]

Thanks to you both. I think I'm going to try it.

 

[bandit788]

Hey guys, can you take a standard four pin Molex, and mod it to have four separate LED wires? I wanted to take four 22ga wires (with a resistor in each), hook them to my 12V molex pin. Take the four corresponding negative LED wires and hook them to one of my two molex ground pins. Pop the pins in the molex connector and have four LED cables going in different directions. Will it work???
Bandit

 

[four4875]

i dont see why it wouldnt work. you could either use one resistor for all 4 of them, or seperate resistors for each LED. either way, long as you calculate it right youll be good.

 

[bandit788]

Thanks four, I've ordered my supplies and I will be wiring in no time. I think it will work. If anyone wants resistors you can buy them at Mouser.com, about any ohm, 100 for $1.40!!! Probably will never need a 100, but who knows.

 

[SolidxSnake]

Hey guys, can you take a standard four pin Molex, and mod it to have four separate LED wires? I wanted to take four 22ga wires (with a resistor in each), hook them to my 12V molex pin. Take the four corresponding negative LED wires and hook them to one of my two molex ground pins. Pop the pins in the molex connector and have four LED cables going in different directions. Will it work???
Bandit

That's called parallel wiring.

 

[bandit788]

SolidxSnake, in parallel my current draw should be fine with four LED's, should it not?