Counting pins on IC?

Discussion in 'The Projects Forum' started by kyroguy, Sep 2, 2010.

  1. kyroguy

    Thread Starter Member

    May 12, 2010
    Struggling with a project and trouble shooting any small mistakes I may have made along the way. Anyway, I come to the realization that I may have the IC in backwards. I have always counted the pins counterclockwise from the dot or notch on the IC. Pin 1 in upper left and pin 14 in the upper right. Anyway, I start looking at my cd40106b and realize that there is a notch on one end and a dot on the other! Which end do you count from then?

    In the picture you can see the opposite ends of the chip and their markings. I just can't figure out what I'm doing wrong! Every time I try to same money by making it myself, this is what happens...
  2. Papabravo


    Feb 24, 2006
    The notch is adjacent to pin 1. The dot is irrelevant for pin counting.
  3. Ghar

    Active Member

    Mar 8, 2010
    I always check the datasheet for the orientation. It's generally not a big deal because you need to look at the datasheet for the pinout anyway.

    The notch is the marking, that dot is a byproduct of manufacturing the plastic case.
    If there's a dot it would be a circular indentation or a printed dot.
    Remember that machines need to sense the direction so it will either be very obvious visually or mechanically.