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Driving a 10 watt LED

Discussion in 'LEDs and Optoelectronics' started by Orion96, Oct 9, 2016.

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  1. Orion96

    Orion96

    26
    2
    Dec 18, 2015
    Hi everyone

    I want to play around with different LED lights and strips, I bought a 5m 30 watt strip, a 4 watt COB and two 10 watt COB LEDs. Also a 5 amp 12v power supply.

    My question is....
    how would I go about driving the COB ones?
    Are the strips safe to power directly off of the PSU?

    Thanks in advance.
     
  2. hevans1944

    hevans1944 Hop - AC8NS

    4,606
    2,151
    Jun 21, 2012
    There is a resource page on this forum that explains how to drive LEDs.

    All LEDs require some means to limit the current. LED strip lighting usually has this built into the strip for powering the strip directly from a voltage source. COB LED arrays generally do NOT have current limiting built in. You must carefully read the manufacturer's datasheet and determine typical forward voltage drop across the LED array and recommended forward current for rated power input. It is then up to you to devise, purchase, or build an appropriate circuit to meet the COD specifications. Pulse-width modulation of the PSU output voltage seems to be the go-to method, but if you don't mind the inefficiency a series current-limiting resistor will also work.. Don't forget to provide an adequate heat sink for the COB. And visit this forum page to learn how to use LEDs:
     
    Orion96 likes this.
  3. Orion96

    Orion96

    26
    2
    Dec 18, 2015
    Thank you, I shall check it out.
     
  4. Herschel Peeler

    Herschel Peeler

    401
    65
    Feb 21, 2016
    I can only give general responses to vague descriptions. I need part numbers of some kind to get specific. Generally, yes, you need current limiting. That being said, I have a high Watt LED designed for 12 V that I have been running just fine as a desk light for almost a year now. No current limiting, just 9 V power supply heat sink and fan.
    I have LED flashlights that are just three AA batteries and white LEDs, no resistors even. I replace the LEDs in the flashlight about once a year, but I buy them by the hundred.
    The high watt LED (8 to 10 W I think) is powered by a 9 V, 1.2 A wall wart but I think it only draws about 750 mA at 9 V. The LED was bought from Electronic Goldmine, a surplus vendor, so I don't expect it to be "prime".
    Advice ... try it at 9 V, or what ever you have. It won't break driving it at a lower voltage. Heat sink is recommended. Fan is a good idea. See how warm yours gets with a heat sink. The heat sink and fan I use came from an old PC. Yes, the fan says 12 V too but works just fine at 9 V also.
    I have another 10 W LED I power from eight D cells. It is a real kick-ass flashlight. :) Heat sink, no fan. If I leave it on too long the heat sink does get a little warm, but no problems so far. The heat sink is also an Electronic Goldmine item. (I don't pay full retail for many things.)
     
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