please help me

Discussion in 'The Projects Forum' started by rabiprasad, Jun 11, 2013.

  1. rabiprasad

    Thread Starter New Member

    Jun 11, 2013
    1
    0
    need a help ... i have 10 white bright led lights
    and a battery of 6v 4.5ah (cycle use :7.25~7.45v (25 degree Centigrade ))
    (initial current :less than 1.2a)
    standby use :6.8~6.9v (25 degree Centigrade))


    the leds are glowing fine with 3.5 v battery ....
    but i have 6v 4.5ah battery
    so if i connect the leds in parallel ....
    which resistor should i use in each led to glow fine

    i used 1 k resistor (as directed by a frnd) in each led but the light is too low (very dim )
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,979
    744
    I would use a 330 Ohm or 470 Ohm resistor on a 6V supply, what is the current for one led ?
     
  3. wayneh

    Expert

    Sep 9, 2010
    12,101
    3,036
    FWIW, the guys selling cheap LEDs on e-bay often include 470Ω resistors with the intention that it's for a 12V system, giving up to 20mA or so. Personally I would shoot for a lower current (10-15mA is fine) and thus a larger value resistor as recommended by Dave.
     
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