Triangular wave to sine wave

Discussion in 'The Projects Forum' started by cade007, Apr 18, 2006.

  1. cade007

    Thread Starter Member

    Apr 14, 2006
    14
    0
    Is it possible to generate a sinewave from a triangular wave? I need some sort of sinewave generator and all of the chips I have found which generate a sine wave are no longer being sold. Any help would be great!
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    You're probably unable to find the old ICL8038. Go to Mouser Electronics and get an NTE864 (I think the part # is 522-NTE864). It's the same circuit.
     
  3. cade007

    Thread Starter Member

    Apr 14, 2006
    14
    0

    I did see the ICL8038 and another one similar made by maxim, but I couldn't find anywhere that sold the chip. The NTE864 is exactly what I need! Thanks!
     
  4. rdg151

    New Member

    Apr 17, 2008
    1
    0
    I need to generate a 500 Hz sine wave. It would be nice if I could adjust it from 1 to 1000 Hz. I bought an NTE864 yesterday. I've been playing with all the resistor and capacitor values I can think of and I still can't get anything but a 60 hz triangle wave. Can somebody please help me out here? Thanks.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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  6. Thomas.R

    Member

    Aug 16, 2007
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    maybe a wienbridge op amp circuit could do the trick?
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    Of course, and the sine wave would be a lot higher quality than the 8038's. The National Semiconductor op amp collection has one in it.
     
  8. Wendy

    Moderator

    Mar 24, 2008
    20,766
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    An op amp integrator will turn a triangle wave into a very close appoximation of a sine wave. It will not be pure, but you would have trouble telling the difference with the naked eye. Here is a variation I've shown several times in other posts.

    [​IMG]

    In this thread SgtWookie was kind enough to do a SPICE simulation, I'll show the thread and the specific post. The thing I like about Sarges simulation is it shows the sine wave.

    http://forum.allaboutcircuits.com/showthread.php?t=10755

    http://forum.allaboutcircuits.com/showpost.php?p=64466&postcount=13
     
    asdfrewq likes this.
  9. SgtWookie

    Expert

    Jul 17, 2007
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    Yep, that would do it.

    However, if he's already purchased and has in hand NTE's clone of the ICL8038, that doesn't help him a whole lot.

    Using that function generator IC to simply generate a 500Hz sinewave is really quite a waste though, I'll have to agree.
     
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