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Basic question about a "breadboard"

Discussion in 'Electronic Design' started by Ignoramus27362, Oct 23, 2005.

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  1. I bought some DIP breadboard. In my naivete, I thought that there were
    power rails on the perimeter, and then every hole in the middle is
    electrically isolated, so that I can connect whetever I want to
    whatever I want.

    It turns out that it is not the case! There are little strips in the
    back of the breadboard so that all points on every "vertical" line
    have the same potential, they are connected. WTF? What is this even
    useful for?

    I wasted a bunch of time laying stuff out on it (started with just a
    555 timer to get some practice), until I realized what was going
    on. (the strips connecting points on every vertical line were not
    visible behind sticky foam on the back. I had to peel that foam to
    see).

    WTF?

    For now, I will try to just solder wires to my 555 timer.

    i
    --
     
  2. forget it, I figured it out. ICs should go in the middle.

    i


    --
     
  3. Pooh Bear

    Pooh Bear Guest

    It's what *everyone* used to use.

    You use a cutting tool to break those strips up as required.

    It's so intuitive to me that I can't actually think of how to explain it
    any better.


    Graham
     
  4. Guest

    The cutting tool is called a "spot face cutter" - usually corrupted to
    "a spotty-faced cutter". A ggogle search on the proper name produced
    this

    http://www.eleinmec.com/article.asp?11

    which does provide an explanation, with pictures. It isn't a great
    explanation - I always solder my integrated circuits directly into
    strip-board, because the sort of sockets that make good electrical
    contact with the IC pins ( and maintain good contact for more than a
    few months) cost rather more than most ICs.
     
  5. This sounds nice. Seems like breadboard is no good for anything byt
    prototyping.

    i
     
  6. Tim Wescott

    Tim Wescott Guest

    If you're talking about the solderless breadboards, AKA "protoboards",
    the ones made out of white plastic that you plug things into then yes,
    they're only good for prototyping -- they fail under high current, high
    vibration, or when the mood strikes them. I find them very useful for
    small stuff where I know I'm going to have to dink around to get things
    right.

    When used properly a _soldered_ breadboard will last as long as anything
    else in the world -- but it's much harder to change things around.
     
  7. Are they called soldered breadboards? Or something else? I would like
    to buy one.

    i
    --
     
  8. Don Foreman

    Don Foreman Guest

    It isn't even good for that where high current, high dI/dt, or RF is
    involved.
     
  9. Tim Wescott

    Tim Wescott Guest

    They're usually called prototyping board. Radio Shack has some that
    exactly match the layout of their solderless breadboards which is handy
    if you have something that works -- you can just transfer the circuit
    over. If you want something bigger, denser, or higher quality look in
    the Digi-Key or Mouser catalogs in their "prototyping" section. Vector
    is the big name, selling "Vectorboard". There's a gazillion options,
    but I usually look for the ones that have three or four holes/circuit
    with interlaced ground and power -- these will do for most lower
    frequency stuff; for RF or high power it's best to just dead bug the
    thing over unetched copper or lay out a board & send it to a quick turn
    house.
     
  10. Joel Kolstad

    Joel Kolstad Guest

    Radio Shack used to sell a regular PCB with the same layout as one of their
    solderless breadboards... dunno if they still do, though.

    I have seen people use solderless breadboards in prototype systems for many
    months at a time (even a year!), and I've even seen people literally box up
    solderless breadboards to ship to someone else who needed access to prototype.
    Obviously this isn't recommended, but my experience has been that the things
    are somewhat more rugged than you might initially expect.

    You can even build single transistor oscillators on the things to better than
    100MHz, although the parasitics start to look pretty significant up there.
     
  11. You see, this thing will operate in a relatively hostile environment,
    inside of a welding machine with a big cooling fan. Hence some
    vibration, although not too much. It will house a gate driver that
    needs to turn gates on and off relatively quickly (sub
    microsecond). Also there could be some EMI as well.

    i
     
  12. Hi Ignoramus
    No, No, itis NOT the right tool for designing Gateunits. Forget this very
    quickly. A gate-Unit for bigger IGBT as you want to use should have

    as short wires as they can (not possible in a solderless breadboard)
    as low resistance as possible (not possible in a solderless breadboard)
    the possibility to give several amperes to the gates (not possible in a
    solderless breadboard)...

    That is the wrong tool for this work.

    Marte
     
  13. "Joel Kolstad" ...
    Yesterday evening it took a collegue 1.5 hours to build a 1800 MHz TV FM
    transmitter on breadboard, and it was spot-on (pun intended) first time,
    good video quality. He added a MAR amplifier today and got a 10 meter reach.
    Total size was about 1 x 1.5 cm, all components in SMD soldered between
    pads. A nice demonstration of what you can do with the stuff...

    Regards,
    Arie de Muynck
     
  14. do you have a picture of the breadboard?


    martin
     
  15. Chris Jones

    Chris Jones Guest

    It's ok for debugging the basic oscillator which only runs at a few hundred
    Hz, but I wouldn't connect it to the welder in case one of the contacts
    went flaky at the wrong time. As you say, solderless breadboard is no good
    for the gate driver, the inductance in the gate circuit should be under
    20nH or so for it to work well.

    Chris
     
  16. "martin griffith" ...
    Should be available this weekend, I'll post a link.

    Regards,
    Arie de Muynck
     
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