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Gates - Basic question from new student

  1. Feb 24, 2009 #1
    OK so I've been reading a lot about gates and Boolean logic lately and I understand how they function but if somebody were to open up the casing of an electrical component and they asked me to point to an 'and' or an 'or' gate what would I point to? Pictures would be very helpful thanks.
  2. jcsd
  3. Feb 24, 2009 #2


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    You'd point to the little piece of silicon that all the leads are wirebonded to. It's just a couple of transistors patterned onto a tiny piece of silicon. (And no, individual transistors probably are not visible to the naked eye--I say probably because it depends on what process was used--hundreds of um used to be a fact of life)

    But if you're looking for pictures, look down in this circuit.
  4. Feb 24, 2009 #3
    Thanks that helped me a lot!
  5. Feb 24, 2009 #4
    this is what you would see in the olden days in school if you were breadboarding logic circuits. http://en.wikipedia.org/wiki/7400

    notice that military-spec'd parts were also available in the 5400 series.

    the 74 or 54 tells you that it is a civilian or mil logic family, and the next 2 or 3 digits the gate or function type. so a 5400 is a military quad 2-input NAND gate. and letters were added over time to accommodate newer gate technologies.

    a classic and still excellent book on these old ICs is Don Lancaster's TTL Cookbook.
    Last edited by a moderator: May 4, 2017
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