Can I use these LEDs on my Mobo

Short answer: More than likely

Long answer: The HDD LED on your motherboard should already be configured to be a current source of around 20ma.

The point of a resistor is to turn a voltage source into a current source, you have a fixed voltage between two points, by adding a resistor R you get a current V/R. Every LED has a voltage drop before it begins conducting current, so by adjusting for that voltage drop you can find the ideal resistor to provide approximately the right current.

EX:
An LED with a 1.5 Voltage drop, and ideal current draw of 20 mA across a 3.3V source.

3.3-1.5 = 1.8V
V=IR thus, R= 1.8/.02 = 90 Ohms.

Now, this isn't exactly rocket science, you can honestly take any resistor from 50 to about 1Kohm and your LED will light (Abiet with varying brightnesses and depending on the quality of the LED, lifetime).
Also the tolerance of the LED depends on the makeup of the substrate, a good blue LED will take 9V without a resistor while a UV led will pop if you have 1.5V and too low of a resistor value.

In short, the resistor is only there to limit current draw, using ohm's law it isn't rocket science to figure out what resistor you need for any voltage source.
 
Thank you, I appreciate that you went into detail too. Being i have never studied this subject before this actually helped and gave me an idea of what i should be researching, and they did work. Again thank you.
 
You must log in or register to reply here.
Back
Top