« previous next »
Pages: [1]   Go Down

Author Topic: PS LED Question  (Read 1638 times)

Offline i7vSa7vi7y

  • Ω Allumnist Ω
  • *
  • Posts: 101
  • Post quality +4/-1
  • Gender: Male
  • Acidmods User
PS LED Question
« on: May 18, 2011, 05:59:39 PM »
Why is it that when i use a resistor calculator for 3.5v forward voltage it says i need a 1/4w 82ohm resistor but in the tut it says use a 47ohm 1/4 watt.
What would be the difference of the two?
Logged

Offline hyper999

  • Acidmods Alumni
  • Millennium Poster
  • *
  • Posts: 1158
  • Post quality +544/-3
  • Research and Development
Re: PS LED Question
« Reply #1 on: May 19, 2011, 01:08:24 AM »
you are using different led to the one used in the tutorial, use an 82ohm one
Logged

Offline whitetop

  • E = MC² Mad Scientist
  • *
  • Posts: 1910
  • Post quality +39/-12
  • Gender: Male
  • im not in the ass kissing team
Re: PS LED Question
« Reply #2 on: May 19, 2011, 01:39:39 AM »
82ohm for a 5mm 47ohm for a 3mm plus its not direct from the battery
Logged
come to the rite place if you kiss admins as they promote you to admin.

Offline TomasR

  • Chief squatting Hard
  • *
  • Posts: 22
  • Post quality +1/-0
  • Gender: Male
  • pm me if u got a cheap/easy rapid fire mod
Re: PS LED Question
« Reply #3 on: May 19, 2011, 02:03:04 AM »
just use the formula : R= U/I
U is your voltage you want to get rid of. probably 0.5 or something since you will need to go from 3.7 to 3.2 V. and the I is probably 0,02 A if you place all your led's paralel.

wich brings us to :  0.5/0,02 = 25 ohms and about the wattage it will come out at 0,01 or something so just keep it as low as possible to save space and money.
Logged

Offline i7vSa7vi7y

  • Ω Allumnist Ω
  • *
  • Posts: 101
  • Post quality +4/-1
  • Gender: Male
  • Acidmods User
Re: PS LED Question
« Reply #4 on: May 20, 2011, 07:48:15 PM »
Ill either use a 0603 smd or a 3mm and there min is 3.0 max is 3.4

So would a 82ohm be best or 25ohm.
I'm new to this resistor stuff. Sorry guys i just don't want to be buying the wrong stuff.
Also i would like them to be as bright as i can get them.
Logged

Offline TomasR

  • Chief squatting Hard
  • *
  • Posts: 22
  • Post quality +1/-0
  • Gender: Male
  • pm me if u got a cheap/easy rapid fire mod
Re: PS LED Question
« Reply #5 on: May 21, 2011, 10:38:23 AM »
well i actually found out that my controllers only run with 2.8 vols so i dont need resistors since leds are all 3.3 volts (exept red ones, i place them 2 by 2 then they are 3.6 volts). but i think 25 is enough since i think if u use 80 ohms you wont have any light left and with 50 ohms or some thing you would ruin alot of power..... but ye,
Logged
Pages: [1]   Go Up
« previous next »
 
SMF spam blocked by CleanTalk
SimplePortal 2.3.5 © 2008-2012, SimplePortal