Stainless

Ok, well I'm modding my PS2 and I'm using LED's, I'm trying to power them off a 7v line on my playstation. So I got 4 LEDs (2v each) and wired them in series and overvolted them on a 12vtransformer I have to see if they worked, and they did! Nice and bright Anyway, I went to put them in my playstation, I wired it all up and pressed the on button - nothing, LEDs didn't light up, the playstation was working fine, so I didn't short it out or anything...

So then I could "Maybe there isn't a good connection on my solder" so I put my 2 UV LED fans on the same line and turned it on - They worked!, so then I ran the LEDs and the 2 fans on the 7v line, and the fans lit up fine and nice, but the LEDs still didn't light up...

So I took the LEDs out and tried them on the transformer again and they worked....

Why the hell wont they run from the PS2? Any ideas? It's a real mystry to me... They're better rated (4 in series = 8v) than a 12v fan, and draw less, why is it a problem?

kuhli

If they are rated 2volts each and you have them in series that equals 8volts which is 1 volt too low. Leds are not like incandescent lightbulbs they won't work untit the threshhold voltage is reached.
Try it with 3 leds.
Kuhli

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Stainless

They should just be undervolted by 1v though, right? really, each LED is undervolted by .25v, not 1v each... I will try though, thanks.

-Thrilla-

no the voltage don't add up, it's the resistance....
so you have 2v LEDs off a 7V line
do you have any resistors? if so, what ohm

fstfrddy

Listen to Thrilla, he knows what he is talking about and educated me on LED's

-Thrilla-

lol i actually did lots research on the internet and talked to my dad about LEDs when i was building my case mod. i had 50 LEDs to deal with....

fstfrddy

Got me going all I needed to know, Thanks

Stainless

Me and Thrilla talked about them on another thread I created about how to wire them, and I've chosen to wire them in series, because then no risitor would be needed (as we figured out). Anyway, I tried 3 LEDs and they still didn't work. I've just got 4 leds in series, no risistor.

-Thrilla-

what are the amps again?

Stainless

Well I'm using standard 5mm Red LEDs, the packaging says nothing. I'm guessing 10 - 20mA? There's enough amps to support two fans, (Both with 4 leds) so why can't it support 4LEDs on thier own?