Author Topic: Resistor Question  (Read 3019 times)

Offline crazyl69

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Resistor Question
« on: December 11, 2007, 08:54:11 PM »
         To begin, I'm new to this forum and this is my first time posting. I'm working on a friends psp (trigger mod) and would like to use red led's. I understand that red led's are of lesser voltage (2.4) than the blue led's of (3.5,5.0) volts. What number ohm resistor can I use in order to properly power up the low voltage red led's with out having to worry about burnning them out.        Edit: would the 10 ohm resister still be good enough or a higher ohm be necessary. Any help would be highly appreciated. Thanks...

Offline Azie139

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Re: Resistor Question
« Reply #1 on: December 11, 2007, 09:02:40 PM »
i think 10 ohm should be good

Offline l0rdnic0

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Re: Resistor Question
« Reply #2 on: December 11, 2007, 09:23:57 PM »
10 might be good but when in doubt look up LED Calculator on Google....  You just need to know your supply voltage (5volt on a PSP in most spots) and you fwd current.. in your case 2.4 and the miliamps your led opperates at..

 :hifive:

http://ledcalc.com/

or

http://www.hebeiltd.com.cn/?p=zz.led.resistor.calculator


L0rdNiC0 Pioneering Mods on the PSP Slim :taunt:
Sound Mod, Button LED Mod, Security Mod, Dual NUB, Mode Select Switch + More

Offline BABYGOAT

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Re: Resistor Question
« Reply #3 on: December 12, 2007, 01:00:41 AM »
86.666 Ohm resistor.

Input voltage  minus forward voltage for led =

5.0V - 2.4V = 2.6V

Answer divided by LED current = resistor value

2.6 divided by (usually 30 mA) 0.03 = 86.666 Ohm

Done!!!

Someone correct me if i am wrong?
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