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LED polarity marking -- not?

Discussion in 'Electronic Components' started by mc, Jan 1, 2008.

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  1. mc

    mc Guest

    Normally, I thought LEDs had the flat side on the cathode (like the stripe
    on a conventional diode).

    Yesterday I found some (Digi-Key Part P410-ND) that have the flat side on
    the anode (both in real life and in the diagram on the Digi-Key catalog

    How common is this?

    Like other LEDs, these still have the anode lead longer than the cathode.
    But once you cut the leads, that feature is of course lost.

    Incidentally, these P410-ND LEDs are a high-brightness type that work very
    well in making POV displays (showing letters in the air as you move it past
    you). They are quite visible with just 2 mA of drive current.
  2. Ecnerwal

    Ecnerwal Guest


    What about the guts? Normally the cathode is the big hunk of metal and
    the anode is the small hunk of metal, looking inside the epoxy.
  3. mc

    mc Guest

    Right, the "guts" were not reversed... if you line up an old and a new LED
    together by polarity, they have the "guts" in the same direction, but the
    flat sides are opposite.
  4. Not a reliable "indicator". Super-bright reds are the opposite.

    Best regards,
    Spehro Pefhany
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