82 ohm resistors needed?

[sergster1]

Yeah I would love to do a ROL mod for my psp 1000 with red 0603 LEDs. The instructions call for 10ohm resistors. However when trying to find the wattage my resistors need on ledcalc.com I saw that they recommended 82 Ohm  resistors. I find this semi odd that the resistor its asking for is around 8x the one the instructions call for. Can someone check the specs of the LED (will post below) and give me a second opinion on what type of resistor i need? Thanks in advance.

0603 Red LEDS: Forward Voltage: 2.1 - 2.3 Forward Current: 20 mA MCD: 100 Dominant Wave: 635nm

Also im looking to utilize 2 LEDS for the ROL mod.

[jrfhoutx]

source voltage might help as I hate having to dig around to find the source voltage people are working with. Now I will tell you from experience that a 10ohm resistor will work though most likely lessen the life of your LEDs. but personally I think the 10ohm resistor thing was a typographical error made by CyberPyrot (as he started the whole thing) and no one ever questioned it (as not many members ever wanted to question anything he said) since 100ohm resistors seem to be the magic number for red LEDs in just about every other gaming device...

I'd say follow what the calc is telling you and try it with 100ohms I'm not sure they make 82ohm resistors, so in the case of it not being made go to the next highest resistor value unless the next lowest value is closer to your calculated value, eg. you calculate 82ohms, the next lowest is 80ohms, the next highest is 100ohms, go with the 80ohm; you calculate 82 ohms the next lowest is 50ohms, the next highest is 100ohms, go with the 100ohm...) and it'll probably work out really well for you...

[FOOKz™]

yes. having a higher resistor for your LEDs won't hurt because actually the higher the resistor value the more it will protect your LEDs from damage but on the other hand the higher the resistor the dimmer the LEDs will be.

Hey if you have a camera phone you can show off some of your work.

[zephyr1220]

Is it really necessary to put a resistor to each LED?
I am new to modding and i was planning to do trigger and ROL mod on my phat.
Ill post some pics after i put decals on.
Thanks!!

[jrfhoutx]

yes you need resistors for your LEDs, you don't neceessarily need to do individual resistors for each LED if wired in parallel but you need at least on resistor on the ground leg that is equal to the total resistance that you would put for each LED. if you're doing 5 leds and it says you need 5 80 ohm resistors then 1 400 ohm resistor on the ground leg

[zephyr1220]

I see...
Got another question, ive noticed that there are no resistors used in direct contact sound reactive LED mod(w/o the amplifier ic) will this affect the lifespan of my LED?
Can i direct contact it to the speaker and put some resistors on it?

Thanks for the quick response!

[FOOKz™]

speakers use a certain kind of current flow because the electrical sound signal that goes to the speaker does not effect LEDs the same way as a regular battery will.

But yes Please still use resistors for the sound reactive led mods... its very good practice so your LEDs won't die ever!!!

[zephyr1220]

Thanks for the advice sir!
I'll use the right resistors ill report back with results and pics.
Thanks so much!!!

[FOOKz™]

Awesome! Can't wait to see