HOW Do You Design a Working Circuit?

Discussion in 'The Projects Forum' started by quicksilver, Aug 12, 2008.

  1. quicksilver

    Thread Starter Member

    Mar 6, 2008
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    This may seem like an extremely simple question but my purpose is to compress what is written as a schematic....I always thought I was creative but I have a tough time DESIGNING a working smaller circuit from a schematic.

    Many of you have ways of taking a written schematic and designing a circuit that is smaller and more efficient than the written outline. HOW do you do it?
    I have heard from some that they start with the most complex components or those needing a heat sink and work outward.
    I have tried that but still come back to the simplistic right angle drawing for my circuits in many cases. How do you make these more efficient and compress or foreshorten the traces and connections? Or is this really only a product of time and personal creativity?

    Are there any "tricks" taught in engineering regarding this? When you look at a schematic how do you visualize it as a smaller, efficient functional circuit?
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    This is the most important thing. To make a good design you need to spend time. An advice for the tracks is to pass them where it is possible under resistors, diodes or whatever component you can but be careful not to create shorts.
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Learn the basics, start small, and think in terms of building blocks.
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Like many learned things, it's practice, practice, practice. I often look over layouts and see ways to rearrange the components to improve the path of the traces and use less area.

    When I first started, the method was to do the layout on paper using double-sized component outlines from a template. Rearrangement was almost more trouble than it was worth. Going to a CAD program made life much easier. But I can still route traces by eye better than the program.
     
  5. roddefig

    Active Member

    Apr 29, 2008
    149
    0
    "The Circuit Designer's Companion" by Tim Williams is the only book I have come across that covers general PCB layout. Amazon link

    The internet contains some good tutorials that you might be able to find with a little googling.
     
  6. yubyub

    Member

    Aug 13, 2008
    19
    6
    I'm guessing you mean taking a circuit schematic to pcb schematic. Personally whenever I've done these, I've spent a good 30mins setting up the rules for an 'autoroute' then from there using normal ideas to make it neater/better.

    or if you already have a pcb schematic... same kind of deal, in your mind label what you want to achieve, and go at it in a systemised kind of way that you think might work best.

    My personal preferance is to have knowledge of the circuit, before chosing where to put components, then putting stuff like resistors lined up beside each other really close, with straight tracks, etc.

    My personal experiance with cad 'autoroute' is that if you set it up right, it works well but does some silly things. As long as components are placed intelligently it shouldnt be too much work from there to something finished.
     
  7. quicksilver

    Thread Starter Member

    Mar 6, 2008
    19
    0
    Indeed, I'm talking about not having a PCB just a schematic on paper.
    I can't tell you how important these suggestions are I honestly appreciate the suggestions. It seems that this is not so unique after all (I thought I was the rare person who ever pondered over the more efficient use of space and layout: that to the majority, it was second nature.

    As bizarre as it seems when I think about it, it's not the simplistic or complex circuits that give me trouble but the "middle-level" designs. Where a large number of components are concerned, often (it seems) the right angle layouts are often just fine. The simple circuits are not too difficult to compress; as I can see the unused space and ways to compartmentalize the traces. But the designs that are "in between" are quite a challenge. Especially those that make use of oscillators or "direction" that energy must follow.

    Using "EXPRESS PCB" or "EXPRESS SCM" actually seems a bit slower than using paper and pencil (to me anyway). One thing that slows me up a great deal is the older concepts I remember of common ground designs when I was a lot younger. I had a long lay-off in this hobby and the IC was not available when "Heath-Kit" was the thing to buy and Radio Shack was actually a store for components & hobbyists.

    I suppose that right-angle design is written for clarity but most all from professional PCB's make use of curves. I often de-solder existing items to get the components and once thought it would be great to be able to actually use the naked board to design a different project. But I suppose you would REALLY have to be pretty sharp to take an existing trace design and work with THAT. But I'd bet someone out there can do it!

    Thank you all very much for your input on this subject: not only is it helpful but I can see how different approaches to the same end are available. The book was a good tip. It's not cheap but I'll think I'll buy it!
     
    Last edited: Aug 13, 2008
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