Help 5W led star 700ma puckdriver

Discussion in 'The Projects Forum' started by homersimpson2473, Jul 3, 2009.

  1. homersimpson2473

    Thread Starter New Member

    Mar 6, 2009
    7
    0
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Yes, you can use the powersupply to pointed at.
    The converter will take about 5 / 0.95 = 5.27 Watt, the powersupply can deliver 12 Watt.

    Greetings,
    Bertus
     
  3. homersimpson2473

    Thread Starter New Member

    Mar 6, 2009
    7
    0
    Hey how did you come to that conclusion that it would work just for my own future reference. What do I have to know for something like that. Is it simple ohms law? Thanks for your time.
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    I just had a look at the datasheet.
    I see that the efficiency at 12 Volts is about 90 %.
    This means that about 10 % of the input power will be converted to heat and is unusable.
    The input power will be outputpower / efficiency -> 5 / 0.9 = 5.56 Watt.
    I add the efficiency graph and connection schematic from the datasheet.

    [​IMG]


    [​IMG]

    One last note:
    The led should be mounted on a cooling piece.
    If the led is used without cooling the lifetime can be very short.

    Greetings,
    Bertus
     
    Last edited: Jul 4, 2009
  5. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    The best way to get it, is to measure it with a multimeter.
    If the sign of the measurement is positive the pins are connected correctly.
    (the red is positive and black is negative).
    If the sign of the mesrurement is negative it is the wrong way around.

    Greetings,
    Bertus
     
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