led in parallel

Discussion in 'General Electronics Chat' started by FroceMaster, Dec 13, 2014.

  1. FroceMaster

    Thread Starter Member

    Jan 28, 2012
    400
    4
    hi
    if i connect this ,will the density on each LED be the same ?
     
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  2. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    It is not wise to connect leds directly papallel.
    They can have some spreading in the forward voltage.
    The one with the lowest forward voltage will get the most current and most likely will fail first.
    When that one has failed, the others get more current and so on.

    It is a good practice to give each led its own current limiting resistor.

    Bertus
     
  3. paulktreg

    Distinguished Member

    Jun 2, 2008
    611
    120
    If you could up the supply to 12V then putting your LED's in series with one resistor is an option?
     
  4. ramancini8

    Member

    Jul 18, 2012
    442
    118
    The answer is NO. Bertus is correct; furthermore, depending on the brightness matching you desire you will have to adjust each series resistor to obtain the matching. That said, they won't stay matched (depending on your definition of matching) because temperature, age, voltage variations, etc. will cause brightness changes.
     
  5. cmartinez

    AAC Fanatic!

    Jan 17, 2007
    3,571
    2,535
    And if you'd want to gild the lily... then individual current control would be the thing, that's always the best (and most complicated and expensive) way to drive an LED...
     
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