35mA led with 25mA pic output?


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  1. #1
    xnihilo's Avatar
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    Quote Originally Posted by RussMartin View Post
    You are misreading the table.

    The third line is saying that the maximum DC forward current is typically 35 mA. It means that for some of the LEDs, it may be a little more and for others a little less, but what it is telling you for sure is, "Don't exceed 35 mA."

    The first line of the table is probably more indicative, where it shows a typical forward voltage (Vf) of 2 VDC when run at 12 mA. This sounds like a typical operating condition and is probably as bright as it needs to be.

    So you need a series resistor of 220 ohms (13.6 mA), but you can probably use down to 150 ohms (20 mA).
    ... Right. Thank you.
    Stuff like "Vcc=Min,Iol=MAX,Vih=MAX" is not yet so obvious for me.

  2. #2
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    .....Information removed at the risk of annoying RussMartin......
    See post below....
    Last edited by skimask; - 29th October 2008 at 11:48.

  3. #3
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    Quote Originally Posted by skimask View Post
    Most of those abbreviations are listed at the bottom of the pages of the datasheets.
    If not there, usually a Google-search and/or Wiki will get you the answer on whatever the abbreviation means. In this case:
    Vcc = voltage common-collector, generally positive voltage input
    Iol = current, output, low (sinking current)
    Vih = voltage, input, high
    . . . and which have nothing to do with either his question or his LED. I believe he was conveying his thanks to me, not asking another question.
    Russ
    N0EVC, xWB6ONT, xWN6ONT

    "Easy to use" is easy to say.

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    Quote Originally Posted by RussMartin View Post
    . . . and which have nothing to do with either his question or his LED. I believe he was conveying his thanks to me, not asking another question.
    Well excuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu uuuuuuuuuuuuuuuuuuse me

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