Express PCB LED Symbol

Discussion in 'General Electronics Chat' started by tracecom, Jun 3, 2010.

  1. tracecom

    Thread Starter AAC Fanatic!

    Apr 16, 2010
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    Attached is a screen shot of the pictograph that ExpressPCB uses to represent T 1.75 LED's. In their layout tips, they say that a square pad should be used to represent the positive lead in a polarized component. I am confused by what seems to be a contradiction.

    The flat side of an LED is (usually) the cathode, which is the negative side, right? And yet they use a square pad to represent the cathode. Or am I wrong as usual? :confused:
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    It really doesn't matter. Put it on the anode side if you wish. Typically I use a square pad to indicate position 1 of a header/connector,etc...
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
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    That is the convention for LED's. Just recall that the LED cathode is the short lead.
     
  4. n1ist

    Active Member

    Mar 8, 2009
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    Actually, that's the convention for diodes in general. For parts with numbered pins, the square pad is used for pin 1.
    /mike
     
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