LEDs

I'm looking to get some new LEDs for the front of my case. Radioshack.com has some nice bright blue ones for $4 a pop :eek: , but they're rated @ 3.7V, not 5V that the motherboard supplies for the case LEDs. Is this overvoltage gonna cause a problem? Has anyone done this?

I don't wanna fry $4 LEDs.

You need to use resistors to reduce the amount of voltage going to the LEDs. Use this formula for calculating the resistance needed:

Ohm = (Mains Voltage - LED Voltage) / LED Amperes

So if you had a 1.5v LED that you were running to 5V power it would be:

Voltage = 1.5V, Amp = 0.015 A. Therefore, to calculate resistance needed for a 5V line-in;

Ohm = (Mains Voltage - LED Voltage) / LED Amperes, so;
Ohm = (5 Volts - 1.5 Volts) / 0.015 A
= 233.33 Ohms or 240 Ohms

Remember, the Yellow lead on molex is 12v and the red lead is 5v.

Also, Allelectronics.com is a good place to get needed electronic equipment. They do have 5v blue LEDs for $2.85 a piece.

<a href="http://www.allelectronics.com/cgi-bin/category.cgi?category=340&item=LED-74&type=store" target="_blank">http://www.allelectronics.com/cgi-bin/category.cgi?category=340&item=LED-74&type=store</a>

If you don't want to use a resistor radio shack also has a 6 volt 5mm Blue LED for $2.99 each. I have one of these LEDS and I have not run it long term with my power supply but During test setups it ran for more than 5 min at a time and it still works.


<a href="http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CT LG%5F010%5F012%5F002%5F009&product%5Fid=276%2D311" target="_blank">6v 5mm LED link</a>

Those links are great, thanks guys.

radioshack's website really sucks, I spent at least a half an hour looking through it and all I could find where the 3.7v ones for $4.

Thanks for the link deseqer and thanks for the resistor info aplus, that's sure to come in handy in the near future.

I'll be posting some pics very shortly of my first mod!!