What are discrete gates?

Discussion in 'Homework Help' started by tquiva, Oct 23, 2010.

  1. tquiva

    Thread Starter Member

    Oct 19, 2010
    176
    1
    Hi guys. I have a really simple question for my hw.

    The problem states:
    Realize ALL of the following functions simultaneously using one 4-16 decoder and OR gates. Compare the resulting chip count with a solution using discrete gates only. Assume all inputs and outputs are in positive logic only.
    1. W = A' * B * C' + A * B + A * B' * D
    2. X = A * B' * C' + A * D + A * B' * C + C' * D'
    3. Y = B' * D' + A * C' * D + A' * B' * C'
    4. Z = A' * B' * D + A' * B * D + A * C' * D' + A * C * D'
    Implement these functions in a LogicWorks Circuit Diagram using a '154 decoder chip and any '04, '00, ;10, '20, or '30 devices needed.

    I already implemented these functions using a '154 and a bunch of OR gates. However, it says compare this chip count with a solution using "discrete gates only." What exactly are discrete gates?
     
  2. Georacer

    Moderator

    Nov 25, 2009
    5,142
    1,266
    The question refers to single logic gate IC's, such as 7400 or 7404, that implement only one basic (or almost basic) boolean operation (NAND and NOT respectively for this case)
     
  3. DonQ

    Active Member

    May 6, 2009
    320
    11
    Discrete gates mean the simple gates, not including things like decoders and flip-flops. This would generally only include AND, OR, & NOT, and maybe the NOT output versions NAND and NOR. The original list included NAND (which could be made from NOT and AND), but this means less gates if this is also allowed. If NAND is allowed, how about NOR? Sounds like it deserves a question to the instructor about which "discrete gates" are to be allowed.
     
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