2-4line decoder help please

Discussion in 'Homework Help' started by daniel000, Apr 3, 2011.

  1. daniel000

    Thread Starter New Member

    Apr 3, 2011
    17
    0
    Hi guys

    I'm having trouble with designing a wiring diagram for a 2-4line decoder using only NAND and Inverter gates on a 7400 chip and a 7404 chip for the inverters

    I have found this : http://www.allaboutcircuits.com/vol_4/chpt_9/4.html

    But I'm not sure if the 3rd diagram on that page, with 4 output signals are NAND gates.

    Cheers
    Daniel
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    That's because they are AND gates.
     
  3. daniel000

    Thread Starter New Member

    Apr 3, 2011
    17
    0
    So is it OK to use NAND gates in the position of the 4 AND gates?
     
  4. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,802
    832
    Not as direct replacements. The function/truth table of a NAND gate is different from an AND gate. Research the differences between NAND and AND gates and you should be able to find easily what you need to add to this circuit to make it work with NAND gates and Inverters...
     
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