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What voltage does this LED backlight run off?

Discussion in 'LEDs and Optoelectronics' started by MattP, Aug 19, 2012.

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  1. MattP


    Oct 4, 2011
    Hi everyone!

    I have an LED backlight that I'm trying to power with an adapter. I don't know what voltage I should run it on though.

    There are a total of 40 SMD LED's, in groups of 10.

    I need to 1) find the voltage of the individual LED's, and then 2) find the voltage per group.

    Regarding 2), do I just need to times the voltage of the individual LED's by the number of LED's in the group? For example if the LED's were 3v each, that would be 30v for each set of 10? I expect I'd need a resistor to limit the current as well?

    It's worth noting that each little LED lights up dimly when I use my multimeter's circuit test (beeps when there's no resistance), so the LED's must be quite low voltage?

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    Last edited: Aug 19, 2012
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    LEDs need to be driven from a current source, not a voltage source, so the answer is more complex.

    This may be a good start.
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