design of circuits

Discussion in 'General Electronics Chat' started by Nathan Hale, Dec 2, 2013.

  1. Nathan Hale

    Thread Starter Active Member

    Oct 28, 2011
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    Hi guys! Hope all is well with everyone. I had a question regarding design of circuits.
    Lets take an example of a ready made 4 bit down counter that you could buy online. We all know that it employs flip flops with a ton of gates etc. Now let us say i try to design the same kind of counter from scratch using a truth table , karanaugh map etc .
    Will my final circuit end up more or less close to the ready made IC's circuit? What I am trying to ask is if circuits that behave similarly will have more or less the same gates/components/ circuit diagrams?

    Thank you
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Like re-inventing the wheel for example?
    Max.
     
  3. adamclark

    Member

    Oct 4, 2013
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    I was talking about this in a thread earlier. I have been interested in electronics since early teens. but have only began really learning just recently. and Ive seen tons of schematics, all different but do the same thing.. funny how that works huh?
     
  4. sjgallagher2

    Member

    Feb 6, 2013
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    7
    Not necessarily, for a simple example, think of a NOT gate. You could use diodes, transistors, or even NAND and NOR gates to produce the same function, as well as many more components, but all the designs have the same output. Many circuits are like this, like amplifiers, oscillators, the list is endless! So when each one of these parts to a whole could be made so many different ways the outcome is almost definitely going to come out different depending on the designer. Now when it comes to manufactured parts, they're all about efficiency, and they've tried their best to perfect the designs. It's less likely your design will be like theirs.

    All in all it's like algebra, there's almost always more than one answer to the same problem. (almost being a key word sometimes, like in digital circuits when a circuit is simplified)
     
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  5. crutschow

    Expert

    Mar 14, 2008
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    Some devices can only be found in integrated circuits, such as the multiple emitter transistors used in the input stage for TTL bipolar logic circuits (although they can be emulated using multiple transistors). So, the circuit you make with discrete parts will likely look significantly different from the one inside the IC.
     
  6. JDT

    Well-Known Member

    Feb 12, 2009
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    There are lots of different sorts of vehicles on the road but they all get you from A to B (hopefully)!

    Getting there is OK but how you travel is more important!
     
  7. Austin Clark

    Member

    Dec 28, 2011
    409
    44
    Ultimately the function will remain the same, though there may be a few subtle differences. For example, input and output impedance, voltage thresholds / logic levels, Hold times, maximum frequency, maximum power, etc;
     
  8. Brownout

    Well-Known Member

    Jan 10, 2012
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    It could be. Often there is one way to represent a function in the simplist form. Once in college, I designed and built an NTSC encoder. After that, I read a description of an integrated encoder, and it worked nearly identically.
     
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