I'm looking to switch out my leds that light up for the power and hdd activity, the ones that hook into the motherboard. What kind of voltage does these slots put out? Or is there anything I would need to know when switching these out?
Its all standard TTL afaik from the IDE specs. so its prolly the 3.3v and 5v. either way its enough to be above 0.6v on ANY one i would say its safe to assume (which is above the threashold for 99.99% of all standard logic gates + mcu).
Case-modders will know that a few boards won't run a blue led swapped for the stock amber/green power/hdd one, happen they'll be on 3.3V, majority of mobos have no problem so 5V there seems reasonable.
Are these values normally writting somewhere in the mobo manual? I guess I could dig mine out (wherever it is) and look.
you could always use a multimeter, in the case you dont have one place you tounge on the 2 pins and compare it to 2 AA bateries (ps im not serious)
heh.... well you would need to see whether it felt more like 2 or 3 batteries. My board does 5v... at least my Abit IS7. I haven't checked the epox 8rda3+ (it's in my brother's system... most unmodded except for a premod case). It also depends on LED tolerance... Just test with a multimeter and get an appropriate resistor. I know my power LED uses a 100ohm resistor and my HDD LED uses a 180ohm (or something like that)... LEDs all use different voltages. Depends where you get them, light output, color, etc. Good assumption is a 5v source and a ~3v LED. I think metku has an LED calculator. As for the manual... don't expect to find it there. I can't find any useful technical info in mine, such as 3pin header draw limits, power outputs for stuff like this, and whatnot. You can get multimeters pretty cheap... and although I couldn't imagine you killing your mobo doing this, it's worth not killing LEDs. It's useful for other stuff too
I think bit-tech has an LED calculator, actually. Shouldn't all motherboards output the same voltage? That way not matter what case you buy, the LEDs will work in it?
You would think. But there was also a company that made non-standard USB headers and now we have to deal with the stupid individual pins.
You don't need a calculator or another resistor, the one already fitted on the mobo for the standard 2V case led will light a 3.7V blue OK on most boards. Some Soyo boards won't run blues, may be others.
I got the 3mm Red led listed at this link, and it runs 1.7v forward. Are you saying that I should be able to run my reds fine without a resistor? Or am I confused as to what you're saying?
Led connections (PWR, HDD, SMI,...) on a mobo have the serial resistor embedded on the mobo itself, so: YES CD
