Express PCB LED Symbol

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

  1. tracecom

    Thread Starter AAC Fanatic!

    Apr 16, 2010
    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
    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
    That is the convention for LED's. Just recall that the LED cathode is the short lead.
  4. n1ist

    Senior Member

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