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Is there a standard comparator?

Discussion in 'Electronic Design' started by Michael, Dec 29, 2003.

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  1. Michael

    Michael Guest

    Hi - I was just wondering - is there a "classic" comparator? Like one that
    is the standard comparator used in the majority of circuits that require
    comparators? Thanks alot,

  2. Jim Thompson

    Jim Thompson Guest


    ...Jim Thompson
  3. CFoley1064

    CFoley1064 Guest

    Hi - I was just wondering - is there a "classic" comparator? Like one that

    Hi again, Mike.

    Single comparator -- LM311
    Dual (2 per IC) -- LM393
    Quad (4 per IC) -- LM339

    Mike, you seem to be an intelligent guy. You sound like you're ready to take a
    class in electronics, or at least get a couple of books from the library, and
    look 'em over. Possibly you might want to grab a couple of data books, too.
    For beginnners, I'd recommend the CMOS Cookbbook and TTL Cookbook by Don
    Lancaster, as well as the National Semiconductor Linear Applications Handbook.
    Another choice would be anything by Forrest Mims, who used to write for Popular
    Electronics, and has written a number of things for RS and other magazines.
    Look at a good basic high school/junior college electronics textbook, almost
    every library has several.
    Two good choices which might be (at least initially) a little over your head
    for your library are the ARRL Handbook (try getting an earlier edition used --
    they're commonly available at garage sales) and, of course, The Art of
    Electronics. If you're only getting books where you know everything in them
    already, you're wasting your time. I'm sure many other correspondents would
    have many other ideas on how to start with gaining a systematic knowledge of
    electronics, which it seems you're looking for and need. You won't find that
    on a newsgroup, and there's always the old saw about going to the well too many

    Don't take this as a flame. Electronics is actually a branch of Engineering,
    which is a discipline that requires systematic study to uinderstand. A
    newsgroup isn't the place to do that. And by the way, basic questions should
    be addressed to sci.electronics.basics and sci.electronics.components rather
    than s.e.d.

    I wish you luck, Mike. You seem like you're ready to step up to really
    studying this field systematically.

  4. Michael

    Michael Guest

    (CFoley1064) wrote in
    So those three comparators are pretty much identical except for there
    being different numbers of comparators in the package?

    I've been slowly learning about electronics for a couple years now. I
    pretty much go step by step - I get a component - play around with it
    for a while. That's why I'm asking what the most common comparator is -
    it's my next component to mess around with :) Or actually more I find
    some random most likely pointless project to work on - and then figure
    out how to do it. And the comparator fit the bill for my upcoming one :)

    But don't worry - give me a couple years. I'm currently a freshmen in
    electrical engineering at the university of illinois at urbana
    champaign. I hope my posts will sounds a lot more educated soon :) I'm
    taking my first intro to ECE class this spring (though I looked over the
    sylabus - and it's pretty much just going to be review).

    About SEB and SEC - I try posting in those newsgroups - but no one ever
    replies. Those groups are all but dead.

    Anyways thanks for your, and everyone else's, help. Sorry if I'm
    bringing down the level of this newsgroup - but I really don't feel that
    it's that big of a deal when people are spamming this newsgroup, posting
    about completely off topic things, or just flaming for no apparent

  5. It doesn't bring it down, it adds some flavour.
    Flaming and off topic post are pretty typical for engineering newsgroups.
  6. CFoley1064

    CFoley1064 Guest

    So those three comparators are pretty much identical except for there
    The datasheets for the three are available at the National Semiconductor

    You may want to look at the thread "Electronics Books?" which was posted
    yesterday. There's a number of other _very_ good reference books listed there,
    all of which will be available at your library.
  7. LM393 and LM339 are the same, LM311 is faster.

    It would be a good exercise to study the datasheets of the parts so you
    can see for yourself where the differences are. Comparators are
    typically chosen because of
    o speed
    o supply voltage range
    o common mode input voltage range
    o precision (i.e. offset voltage)
    o output circuit (open collector or totem pole)
    and more...

    As the above ICs are standard parts, they're available from many
    manufacturers. The original is from National (, they
    still manufacture the parts. They've got a few more comparators, too, so
    you can see where they differ. And check out the application notes.

  8. John Fields

    John Fields Guest

    Yes, your questions are perfectly welcome here, and on topic as far as
    I'm concerned. A large number of us here do electronics design for a
    living and pretty much know what the most commonly used "standard" parts
    are since we use them every day. No guarantees on seb, although a lot
    of us hang out there, too.

    The LM311 is completely different from the LM339/LM393 comparators and
    you can get the data sheets for all three at National's site:
  9. Michael

    Michael Guest

    Really? I would expect engineers to be more professional than that - as
    most any engineering field, especially electrical engineering, is a white
    collar profession. I'll just blame it on the hobbyists :)
  10. Paul Burke

    Paul Burke Guest

    And don't ask for more speed than you really need. I got caught out this
    way once, I wanted a little more speed than a 339 in a quad package, and
    active pullups and built-in hysteresis looked attractive too. I went for
    the frighteningly fast MAX944s. I could never stop them chattering. And
    they don't have the standard comparator pinout (they are like opamps) so
    yet another prototype iteration was needed.

    Paul Burke
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