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Logic gates.

  1. Sep 15, 2009 #1
    I've been reading articles on logic gates and What I want to do before I get to school is familiarize myself with what individual components are used in making those individual gates on say a breadboard.I keep searching for it on the web but it just gives me the schematic symbols and not what individual components make up the gate itself.I don't want to just plug in the black chip like most everybody else does,I want to dig in and see it work for myself.If anybody can link me to a website that will show you how to make individual nand,or,and etc gates on a breadboard I would appreciate it.
     
  2. jcsd
  3. Sep 15, 2009 #2

    MATLABdude

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    Science Advisor

  4. Sep 15, 2009 #3
    Oh man I'm going to be busy for hours now.Thanks much MATLABdude
     
  5. Sep 15, 2009 #4

    berkeman

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    Staff: Mentor

    Keep in mind that a breadboarded version of a logic gate will be much slower than an actual IC gate. Can you tell us why?
     
  6. Sep 15, 2009 #5
     
  7. Sep 15, 2009 #6
    No idea,I haven't even started school yet.I just want to arm myself with enough knowledge ahead of time to give myself an edge.Why is it that they are slower?
     
  8. Sep 15, 2009 #7

    berkeman

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    Staff: Mentor

    Fair enough. It has to do with the capacitance of the junctions and interconnects. When you wire things up from discrete transistors on a breadboard (or PC board), you will end up with a couple pF or so per connection. That slows down the currents that flow, since they have to charge and discharge those capacitances in order to change the voltages.

    In an IC, the size of the interconnects are much, much smaller than a breadboard, and the capacitances are a couple orders of magnitude smaller than a picofarad. In general, the smaller the IC geometry, the lower the capacitance, and hence, the faster the circuit can toggle.

    Have fun in school !!
     
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